Kristof Tuts interview (English)

Kristof Tuts is a very talented programmer, very active in Vectrex scene who developed two real jewel gems in Vectrex crown, Vectrexians and Vector Pilot.

I don’t think that you want further explanations and infos about these titles or for Kristof Tuts himself.

I know Kristof quite a while since 1999 or 2000, can’t remember exactly… when I set my site online. It was about Exerion arcade game. My thought was to collect every possible piece of info I could gather, to help MAME devs to buid a solid and proper driver for it. My quest all over the web and newsgroups, led me to find Kristof’s Vectorion screenshots, his unfinished Exerion’s port for Vectrex. I did contact him immediately and this was the beginning of our friendship !

I am also a great Vectrex fan ! Yes, I admit it ! I adore this cute and unique black box with laser graphics screen ! This cherished Vectrex passion was our strong common point so we established a good communication since then. My decision to take Kristof an interview came as a consequence which he gladly accepted !

You can pay a visit to his web site @  and if you are a lucky owner of the mighty Vectrex don’t forget to order your own Vectrexians and Vector Pilot copies !

I would also like to thank all my good friends – dR_wHOnickednkary, here in for all their help, patience and hospitality !

Enough with talking !…I hope you will enjoy reading our little chat as much as we did 🙂 ….



– Good evening George. This is Kristof from Belgium !

– Welcome Kristof !

– Thanks for the “Welcome” 😉 !

– We are all very glad to have you here @ iamretro. Thanks for your time to give me this interview!

– No problem George. I was trying to find some time. Time is very precious for all of us, so please forgive the delay in setting up this interview and responding to the questions.

– Let’s start with some details about your background as a lucky Vectrex owner and game player.
When did you get your very first Vectrex console ? Did you own any games then ? Which ones ? What was your favorite Vectrex title ?

– Well it’s a long story; actually it took me quite a while before I had my first Vectrex console by myself.
I was introduced to Vectrex in 1982 in a local toy shop where it was a Vectrex demo stand, the “ball” type stand, and I was impressed with the nice graphics of Minestorm.


It was very nice to see all these nice Mine Storm vector images with the blue overlay and the phosphor igniting, it made really a good impression to me, but I couldn’t afford buying one. I had a friend a few years later who was quite spoiled actually, he had a Vectrex and I spent a lot of time with him playing games like Armor Attack, Mine Storm, Rip Off …But my most favorite game from the originals was Star Castle because it was very well done, at that time and my second-best one was Armor Attack .


It was later, at the beginning of the ’90s when I got my first Vectrex console on a flee market. I was a student then, I was studying electronics at high school and I became passionate for programming on microcontrollers and…yes…I opened the Vectrex I bought and I saw it was containing the Motorola MC6809 processor.

vectrex cpu_insideVectrex motherboard

I knew the  6809 earlier during my studies and it was a pleasant surprise to find out that this was the Vectrex cpu. Then I thought that maybe if I had more time I could start doing some development on a Vectrex.

– Did you own another home micro in that era ? (Commodore, Sinclair, Amstrad, Atari etc..)

– No, no unfortunately not. Nothing. I couldn’t afford one back to those days but I always had nice friends who always had either a Vectrex, or an Atari 2600 or a Commodore 64, so I spent a lot of time with them and my friends. Back to those days, in the beginning or middle ’80s, I was not into programming at all because I had nothing to program on! I was more into real hardware of electronics.

– Any other program(s) or demo(s) you wrote for another home system (8bit or 16bit) ?

– No, unfortunately not. Vectrex is the only home system I develop for. I would love to do something on Genesis, SEGA Genesis, but this is something for the future not for today…

– Do you enjoy playing (arcade) games? Are you into retro gaming ?

– Of course ! I really love the golden era of arcades, ’70s and ’80s… I really loved it, I really lived in it and took full experience of it ! Today we have MAME which I use to play arcade games and I also have a small collection of arcade pcb’s but definitely when I play games, they are arcades from the ’80s like Moon Patrol, Gyruss, 1942 or Gaplus (that’s one I like to play) and Ghosts ‘n Goblins is really nice.
I have also a real Mortal Kombat I arcade cabinet, a smash hit from 1992 ! I bought it a few years later in 1994 or 1995, I think. I bought it original because I wasn’t happy at all with the home versions of it like these for SEGA megadrive or Super Nintendo. It’s still working so I am very happy with this purchase !

– Do you own/collect other consoles or arcade games and what is your favorite one ?

– Although I don’t consider myself as being a collector, I have some consoles and some arcades :
Let’s start with arcades…I have a Mortal Kombat I arcade cabinet (If you want I can send you a picture of it 😉 ), which is in a very good condition. Through the years I also built a MAME PC which I put into the cabinet and now I can switch between the original arcade and the MAME PC. I built also one myself back in ’90s which contains a SEGA genesis and a Playstation console inside… So the consoles I still have, are a Playstation and a SEGA Genesis… that’s all I have and you can say that the original Playstation is my most recent gaming console. My one and only son is also into gaming and has a Nintendo 3DS which he likes to play but I am not into that kind of games, so definitely I am into golden age of classics of the ’80s. And of course, I have 4 Vectrex units as well !

– What is the Vectrex’s magic element that motivates (or used to motivate ) you to program and write games for this console ?

– Well the magic is really the hardware itself !
All these vector graphics, the crt tube, the phosphor that comes alive in the screen. It’s really very interesting to see that something you programmed in assembly, a few moments later comes alive on the screen ! You see something moving around, even if it is a simple square or something in rectangular shape that also moves and is nicer to have a color overlay to put it on…it creates such a special atmosphere I think…very sharp, crispy resolution…it’s really nice !
The second important thing that I love Vectrex so much, is that I really love to program in assembler and definetely on the Motorolla’s processors. The Motorola 6809 processor which is used in Vectrex is one of the best processors ever made and so smooth to program in assembler that you almost don’t need “C” to develop something on it.
The thrill for me is really I like to write in assembler (which is also the case in my daily profession) and it’s definitely the technology, the hardware which is real attractive for me to program on the Vectrex.
I also like to push the boundaries of what the Vectrex can ‘produce’ on the screen, to the maximum limit. I like to push the boundary to find faster ways to draw lines and that is always exciting. It’s also nice to see the final result, but it takes lot of time and lot of fine tuning …
I can say for sure, that I spent most of the time in fine tuning a game till I manage to draw and having all objects moving and interacting on the screen without the screen starts to flickering…
That is actually one of the major challenges on Vectrex programming.

– Did you release your games in a particular order ? If the answer is ‘yes’, is there any reason for that ?

– Actually no. There is no particular order.
At the beginning I started develop multiple games at once but I found it very exhausting as I couldn’t finalize all those games one after each other.
For example I started with Moon Patrol (fairly surprising 😉 )…My first attempt on the Vectrex was Moon Patrol and it was a completely different version than what you know as today, the beta version you already have. I think you can find some YouTube movies, small YouTube videos parts, showing way back in 1996 my first game Moon Patrol in a completely different setup. It took me maybe three months to program it and I was getting quickly tired of staying on one game and then I jumped to another game called Vectruss which was also too hard to develop. I did some development on that as well but after a few months I put it on hold and went to next game and that was Vectrexians, the Galaxians clone. I worked for a year on that one and when I got tired of it, I went to Vector Pilot which I think is the only one so close to completion and again got tired and had a “writer’s block”.
When I got tired of programming Vector Pilot, I went back to Vectrexians and I said to myself…”Now, I have to finish it !” and so it happened ! I finallized Vectrexians in 2007 and as soon it was released, I closed that chapter and I continued on Vector Pilot, that came out in 2011.
Next thing I want to do is to get my first game back on track and that was Vector Patrol. This is what I am still doing now, for the last 2,5 years. I rewrote a lot of code of the original game, I examined the original arcade game in a much better way now,  just to analyze what things had to be changed on Vector Patrol.
I think that the game is ok, I find it quite satisfactory. I hope that the players love the game too…that’s another thing, but as far as it looks now and the feedback I got from the testers and also from you…thank you 🙂 , is quite positive ! But again there are still a lot of things to do…this moment I am busy on the animation sequences, extra levels, extra enemy types, there is a lot of unlockable stuff of course…so there are a lot of things still to do. I really hope I can release it somewhere in the middle of 2015.

Vintage video footage of Kristof Tuts’ arcade machine, his first Vectrex console and his arcade boards. Please also notice his Vectruss (0:36″) and Vector Patrol (1′:57″) early designs.

– Which will be the order for your future releases ? Is “Vectorion” next? 😉

– I also love Exerion, George believe me 🙂
First I’m going to release Vector Patrol for sure and then my plan is to take on Vectruss…that is the idea but I can’t promise, I might get tired again and put it on a pause and then take on Vectorion.
Is also a very nice shooter and I really have some very good memories back in the day. I also want to complete that one too ! However it is the one that I have done the least progress till now. I did some tries back in 1999, drawing just a ship, the player’s ship and just one image of the flying enemy bird, you can see it in my web site and that’s it, nothing else.

– “Vectrexians” is great !…

– Thank you! 🙂

– “Vector Pilot” is better !…

– Thank you, very much! 😀

VectrexRoli shows the awesome Vectrex homebrew games : Vectrexians and Vector Pilot made by Kristof Tuts.

– What shall we expect in the future ?

– Hmmm…is very hard to say ! I spent a lot of time with Vector Pilot, to polish it, to make it fast enough, to not flicker at all. I spent a lot of time on the animations between, too much time actually, I was really happy when it was completed because I was really tired working on this game, believe me ! I’m very happy with the results, but I am also happy that it was finished !
What shall we expect in the future ? George, I really do not know if I can hold this level of quality for games like Vector Pilot, because I am also getting older and more impatient, but we will see…maybe I need some rest and maybe I can take up again the programming enthusiasm like back to Vector Pilot days. It was a harsh process, a very long process as well…Finalizing a game is the hardest part. You can write an engine, the main part of the game, quite quickly. Finalizing the game with all the intermissions, extras, catchy music, fine tuning is another drill…that takes lot of time and actually a game is never finished ! As long as you have code available, you keep on adding stuff into the game. So, we will see…
I can’t promise but I will tell this to everybody : “I am always doing my best, what I can and I think that people know it and not complain too much about the quality of my games. I will try to keep that level of quality you are used to !

– I am an arcade player, as well as I am a collector. I own many arcade circuit boards from ’80s. Fact is that your Vectrex ports are nearly identical to the authentic ones. How do you manage this? Playing the original over and over ? Reverse engineering techniques ? Please reveal some magic… 😉

– Well, with Vectrexians and Vector Pilot both my released games, there were not any reverse engineer techniques involved. I really played them over and over again. Real fans of the original arcade will notice differences for sure but I think It’s OK the way it is. With Vector Patrol I did take some peeks in the original arcade, especially some parts of code which control the enemies’ motion, let’s say the attack patterns. I did take a look to the original code on that. It helped me a lot how to find the best way to reproduce the authentic arcade behavior of the game. The rest, the drawing routines, all the normal stuff, aren’t so difficult to make. Most of the code is for drawing the vector lists for all these objects. Anyway you cannot look the original code for that because it is Vectrex and you have to make your own vector images again. It is however useful to take a look at the original code from time to time. I use tools like the debugging version of MAME.
Most of the arcade games of the golden age used a Z80 processor, so you have to learn Z80 assembly language to understand what the processor is doing and then you have to translate that into 6809 assembler which is also a very time consuming process. I think that people will like all the stuff I made for Vector Patrol…well…Moon Patrol’s fans will like it.

– Everything you release is arcade perfect ! How do you achieve this grade of perfection ?

– Well George, that takes a lot of time ! A lot of time to program, a lot of time to test. Sometimes I have to go back to the design table. Sometimes I have to reprogram some stuff, like the game engine. When you program for first time the result isn’t perfect, so you go back to the design table and reprogram it or start completely from scratch.
For example in Vector Patrol. The game’s engine has been completely redesigned. There is almost nothing that I have kept from the old Vector Patrol (the one, I started back in 1996). You can consider the new one as a completely new project. It takes a lot of time to reach a good level of quality, a good game engine which is fun and attractive to play with.

– How many hours, do you spend during development and testing ?

– Well, I am a married man, I have a fulltime job, I have a family and there is not much free time…It used to be different 10 years ago or something. I could say that when I was busy with Vectrexians and Vector Pilot I could work 2, 3 and even 4 hours every evening, on each game. Nowadays…if I can spend 1 hour per evening…1 hour is not enough, believe me…because if you want to get back to the code where you did stop yesterday or something, you will need more time to make the best of it. I don’t have much time to program on weekends either…these are also very short, I don’t have much time to program because I have always something to do.
I think you will understand me on this as well 😉 .

Vector Pilot and Vectrexians cartridges
This is such a difficult thing to calculate. With Vectrexians it is also about the learning curve, eh ? I started Vectrexians in 1999 and it was completed two years later, well the main game at least. I’ am a real slow guy…yes, I know it and I have to give my congratulations to all other programmers who develop games just in a few weeks or few months. I really take my time. Finishing the game, polishing all the edges, adding some extra music, extra intros, screen animations. It is a task that takes a lot of time. I am always into trouble to make decisions for what can I do more, what can I implement into the game, what animation can I make and will be nice to show on the Vectrex.
With Vector Pilot, I started in May 2000 and I finished the main game after one year and a half. It took me some time to implement the 3D animations and some music.
The 3D animations for Vector Pilot took me around two years and a half to be completed. I had to make some tools and to find a proper and fast way to draw these 3D vector images.
Testing ? I make tests during the development, when I develop and program a part of code, I test it immediately to my Vectrex. I try to play the game and see right away the new code come alive, find out if it actually works well. Testing is a process which is running in a parallel way with code writing. I calculate time by adding them both together…programming and testing or developing and testing counts as one.

– How much do you depend on your beta testers ? Are their reports helpful ?

– Yes, but on a certain moment. When the game is 80% or 90% finished I submit my binaries to the beta testers for testing. Sending a binary before that level of completeness doesn’t make sense during development because so many things are subject to change. I submit the binaries when I believe that the game is almost completed.
About the report now…sometimes there is an overlap, different opinions on a certain topic, so I have to take a decision for what will be the best by myself. Beta testers definitely give a good input, a good feedback about their gaming experience.

– Do you discover many critical bugs during beta testing ?

– Mostly not. They are already discovered by me during the development phase. Sometimes it happens, however. If I do a last minute change in the binary code and that causes big side effect and something else doesn’t work or even crashes, then beta testers are very helpful to point me that. Most of the times, when they report an issue I can reproduce it from my side as well. This is very important. If I can’t reproduce a problem that they have discovered, it is very difficult to find the bug or the error in the code.

– Despite the number of animated graphics and quality of music tunes, which are both very memory consuming procedures and give to cpu some extra load to cope with, “Vector Pilot” has a frantic game play…

– Thank you! 😉

Playing Vector Pilot in a dark room…by Vectrexmad.

– …everything acts and moves smoothly with fast paced action. Seems you found the recipe for code optimization…please, tell us some of your secrets in a whisper !

– Well, it’s really a technical issue but there are always possibilities to optimize code, for speed of course. I think there are a lot of good explanations on the Vectrex tutorials which can be found on various web sites. I can tell you some “golden” rules in Vectrex programming…
You must have a fast drawing process of everything, make sure that drawing of everything will be as quick as possible and you do it by reducing the scale factor to a minimum and increasing the coordinates, your vector coordinates to a maximum. That’s the golden rule !
If you want to draw a line of 127 positions or let’s say from top to bottom, you could for example take a ramp of a value of 10 and a scale factor of 127 or even 255, that will work, it will draw a line but it will be very slow. It will be much faster if you would change your scale factor to 12 or 13 and increase your ramp value from 10 to 127. 127 is the maximum value you can give for ramp, because it’s fed to the DAC, to DA converter and it’s only 8bit resolution…so on even sides, that means + or – 127.That’s the golden rule, keep your scale factor as small as possible and your coordinates X and Y, as big as possible.
What else you could do ? When you want to draw an object on the screen the beam first has to “move” to the position on the screen where the object must be drawn and that “go to” operation also, actually a line drawing but with the dot being muted or blanked so there’s no dot that is drawn, it’s really an invisible dot that is moved but this move operation is also most of the times done with the scale factor of 127, most of the games do that.

So you have during the moment of the goto operation 127 cycles available to do some game processing, or collision detection or AI, or enemy strategy updates and so on…I do that often.
What else of optimizations I could think of ?…Yes…these are programming tricks that are all explained into tutorials…like loop unrolling, meaning not using a table of X-Y coordinates but code…I used that with Vectrexians, to be more specific on the way how the enemy objects, the aliens are drawn. The vector list is not so complex, is quite simplified and this is not a vector table of X-Y coordinates but is really a batch of code, it’s really a routine that pushes every Y or X coordinate in code on to registers to being drawn.
The advantage is that you don’t have to look up to a table and fetch the next coordinate and increment the pointer to the next coordinate and so on…you save that amount of clock cycles. Well this is maybe a little thing, a little fact but if you multiply it with a certain amount of factors, which could be in total thousand which you have to draw then, the impact will be significant ! If you can save one cycle for one thousand lines then you have saved one thousand clock cycles.
You know, we need to stay below, let’s say 30000 clock cycles, or on that limit. If we go higher and I mean much higher…let’s say if we go up to 40000 clock cycles for an overall loop, for a loop of the game, then the screen starts to flicker.
These, I think are the basic rules to know how to make the game as fast as possible.
The color overlay also helps against flickering. If you play a game on a Vectrex without an overlay, the phosphor light is in pure white and you will soon notice the flickering. However if you use an overlay which is blue or green, it will reduce the screen flickering. Not all colors have the same efficiency. I’ve noticed that especially blue or green have the best effects. I also use that trick to my games because in some cases I have to go over 30000 clock cycles which leads to screen flickering. The overlay makes that, less noticeable. For some reason the green and the blue average the flicker and it is not so disturbing for the eyes.

– Do you enjoy coding for 68A09 cpu ? Do you enjoy coding at assembly/machine code language ?

– Of course I do ! It’s my favorite Motorola processor ! I do enjoy coding at assembly and that’s the reason I felt in love with microcontroller programming ! Back in my student days, I learned to program on a Motorola 68HC11 microcontroller and it was such a pleasure with a nice instructions set ! Very similar to 6809 with little differences but the concept is the same… you can say that 68HC11’s machine language is a subset but not much reduced of the one of 6809. I did my thesis using a 68HC11 processor, it is a very nice development platform.


I was really happy when I opened my Vectrex and saw a 6809 inside. It is one of the best 8bit cpu’s ever released. The architecture of the cpu is very nice, it’s called Von Neumann architecture, linear address spacing, ram and rom, it’s all the same and it has three pointer registers or even four…you can do a lot of very nice things in one and single instruction.

With other cpus you will need complete subroutines to do the same thing. I really love to program on that one !

– Are you using any specific programming tools ? Have you developed your own tools and apps ?

– Yes. The tools I use to program are the classic ones…I use as09 assembler from Kingswood Consulting or Frank A. Vorstenbosch, he is a Dutch guy. This is a very nice assembler although it has some limitations regarding macros and the content of macros which I am aware now and I can work around it. Other tools I use…I am using MESS, the debugger version of it cause it contains Vectrex emulation inside. It’s like MAME but for home consoles and home computers. However the version I have doesn’t support 64K bank switching so I also use the new version of the mighty ParaJVE from a French colleague, Franck Chevassu aka Parabellum. This is a very nice and helpful tool to check the performance with its viewer. This can show you how many clock cycles one loop can take, or one specific part of code. This is very nice for optimizations.
I used the vector drawing tool from Christopher Tumber, for a while and still use it some times. I also use EXCEL and some Visual Basic for applications in EXCEL to do some stuff like making new font styles. The characters or strings that are all displayed in bitmap style based way in all my new and old games. We have to admit it that bitmap based text is drawn in a much faster way than the fancy vector based ones. I definitely like vector graphics and fonts, I used them on Vectrexians and to some parts on Vector Pilot but drawing vector fonts consumes many cpu cycles so your performance will drop. If you want to draw a long text, let’s say a message with more than three words, then you will notice that it will eat lot of cpu cycles.

3D Engine-1

I also used EXCEL to make the new font in Vector Patrol, you will notice at the new beta version. The original, first beta version used the classic ’80s arcade fonts I used in Vector Pilot. New font in Vector Patrol will be more futuristic style, like the one of “Space 1999” TV series. I think that bonds nicely with the game.


Do not underestimate Microsoft’s EXCEL, it is quite intelligent and you can do a lot, especially when you use it with Visual Basic for applications as a plug in. I used EXCEL and Visual Basic to make 3D rotations and animations of the Vector Pilot and also to Vectrexians, so you know now how all these animations of the Vector Pilot ship are made.

3D Engine-2
Well, those are all my tools I use most of the time.
In the beginning, in the old days before MESS release, I tested everything on the real Vectrex. I made a small hardware bootloader, something like VecRAM. It was a pcb which contained firmware, enough ram and a serial interface. I used to download the compiled binary code into the ram through a program like hyperterminal. I was giving a simple “go” or “run” command, to run the game but I couldn’t debug, I couldn’t step into the code and set break points to discover the possible bugs…that was at the beginning, from 1996 to 2003 and it was frustrating. When MESS came out, I immediately started to use the debugger version and this actually was a big step forward.

– How much data(s) is possible to get squeezed into a cartridge rom ?

– You must know that the cartridge roms I use are the size of 64Kb, divided in two banks of 32Kb. Vectrex can address only to a maximum of 32kb. If you want to address more, you need to use the concept of bank switching. There is one connector pin that switches from low to high (or high to low) and you switch between upper or lower 32K bank. I can give you some numbers…
With Vectrexians the game itself is around 24Kb of rom and all the animations of the rotating Vectrexians ship and the aliens’ ones, are placed in the other 32Kb bank. All these 3D animations are pre computed, I don’t do any rotation in real time because Vectrex wouldn’t be fast enough to calculate all that’s needed in order to do these drawings. It’s all pre computed by one of my EXCEL tools and then it’s stored in rom. Eats a lot of code, it’s true…but actually it was doable. I think that all animations took around 20Kb with Vectrexians.
Vector Pilot was a bit more complex. It was around 24Kb or 26Kb of game code and animations were placed together with the game music in the other 32Kb bank. I found a new way to optimize the 3D animations in Vector Pilot and I could squeeze them more. I had 32Kb of memory at my disposal and I would fill them up with as much animations as I could. That’s the reason I have more animations on Vector Pilot than on Vectrexians. Music have been also compressed a bit more so everything fits fine in 32Kb. The Vector Pilot cartridge is 64Kb as I said but there is not much free space left , I think around 100 bytes or something. The rest is all filled with code.
Vector Patrol now…is a new evolution ! The game code itself is getting really big. I have no animations made yet and the game is already bigger than 32Kb. I do bank switching very actively now. With Vector Patrol all background graphics like the mountains and the moon city have to be located to the second memory bank. There are lots of vector images and there is no place anymore in the main memory bank which contains the game code. This means that in Vector Patrol I have to switch fast between the two banks during every drawing loop. In every loop, there is a bank switch and that is being repeated. The whole process is quite OK as you don’t loose that much of performance. I have already filled 40Kb or 48Kb and I have 16Kb available. Please also note that there is a lot of music inside as well. There is new music added. There is the original Moon Patrol tune to accompany the gameplay. Two more fresh versions of this tune (remix) are inside, too. First is made by Der Luchs, a coder very prominent on proboards web site and the second is a “house – dance” remix of original tune, made by Factor 6, he is a member of the .ay community or .ay scene, makes a lot of chipmusic and he is also kind to lend me his music for this game. I also made a music score inspired by the Police’s song “Walking on the moon“. You will listen to this during the end intermission of the game, the high score entry and so on…it’s really nice. I still have around 16Kb available and I may use them for some ending animations or intro intermissions, I don’t know if that’s possible…
That is for the current limitation of 64Kb. I was once thinking of using multi bank switching because today’s chips are bigger than 64Kb, so there is no problem…but that is something for the future. It is possible to make bigger rom cartridges like 128Kb or 256Kb…that’s true but the bank switching gets much more complicated. This is not a case for Vector Patrol, this will be on a 64Kb cartridge.

– The animated scenes from “Vectrexians” and “Vector Pilot”, are undoubtedly an eye candy but they must eat lot of memory space. Do you plan to use animation sequences to all your future titles ?

– I think that I have already covered this question but…Yes ! If memory size allows me, If I have rom space left…I have now a working environment to render these animations so why not ? It’s only a matter of using your fantasy or imagination of what to do, what should I display.
I was thinking to make something very special for Vector Hopper which it may be my last game, but this is far in the future…

– You are not only a skilled coder you are also an artist…

– Thank you, humbly! 🙂

– You design all these wonderful plastic overlays for your titles. Their quality is something above the highest standards !
How difficult is that ? ….any helper graphic artists ? How much time consuming is this process ?

– Thanks for those very nice words! 🙂
These overlays as you may know, are all silkscreen printed like the old ones back in the day. It took me quite a while to find a silkscreen printer who was willing to do the job. It is a small quantity of overlays. Not all silkscreen printers are used to print on this kind of plastic and use translucent inks. Most printers will print on a t-shirt or cap or something but this is a different job. It needs motivation actually. I finally found , a very nice gentleman who took the challenge and made these overlays. He uses high quality ink and good plastic. I am really very happy with his results. Colors are so nicely saturated when you put the overlay in front of Vectrex screen. Red color is vivid, is not something washed out or some fainted red…is brilliant ! The same for blue and green…green looks very nice, it is a mix of blue and yellow. I am also very happy because people like those overlays.

New OverlaysKristof’s silkscreen printer with some new… surprises 😉

How difficult is that ? Yes, I can answer that…First I make the designs then I passed them to printer guy, telling him what ink colors to use and he prints them. He told me that this kind of ink is not very convenient either because it dries fast and it has some difficulties to handle. The whole process of printing is complex but he finally manages to give me fine results.

silksrcreen printer 1The designs of my overlays are most of the times, simple and…do not laugh ! 😉 …I make them in Power Point and then I give them to the printer. He makes his own manipulations to prepare them for his machine. This process is called “pre press”. Production doesn’t take much time. It takes him one week to process the designs in a specific format to make them suited for his machine and then print them.

– Have you any draft overlays you want to illustrate for our readers ? …any unfinished sketches ?

– Yes, I made some designs for some potential games. This is a bit risky, I mean designing and printing overlays for games that haven’t being developed yet. These are plans I can materialize sometime in the very far future.
I have already made some designs and new overlays for Midway Battles a 1942 / 1943 clone …

midway battles overlay 1midway battles overlay 2

Armor Attack 2, I really don’t know how the game will work but it will be based on Armor Attack original title with scrolling cities and maybe some more stuff, Vectrexians II a Galaga or Gaplus clone…I really don’t know if this will be feasible to do because I had so many problems and challenges on Vectrexians to cope with already, like to draw everything in time without any flicker. This will be more complex because we have much more action in Galaga and Gaplus, like multiple shots, wider shooting base with enemies coming down from the sides, lots of bullets all these will take much more time to do some collision detection, so again we will see…These will be three new games beside my announced ones on my website…Midway Battles, Vectrexians II and Armor Attack 2.
What else do I have ? Yes, I have already overlays for Vectorion…your Exerion, Vectruss, Vector Patrol and also for Vector Hopper !

…from Power Point …

Vectorion Overlay frontVectorion overlay back

…to overlay 🙂  …

silkscreen printer 2

– What do you enjoy most… coding or designing ?

– Definitely coding. I love to code on a such nice machine.
Designing is also a very nice step on the process. I am after of doing them both by multitasking 😉 When I am a little bit tired of coding, I design on overlays but I prefer coding for sure.

– Do you have the same silk screen printer doing the job ?

– Yes, he is the one and only silkscreen “printer guy” I know here who is willing and capable of doing this. Unfortunately he is going to get retired very soon. The overlays that I’ve printed now, will be the last ones. I have to find another place for printing, but there are not many left here in Belgium. It is a dying art, a dying profession because digital printers are taking over. I think that these quality overlays could not get printed digitally but again I am not a graphic artist expert.

– I am a beta tester for “Vector Patrol”. I can assure that this puppy will be an instant hit and it will go straight to the top !

– I hope so ! 🙂 I don’t know to be honest… because Vector Pilot was really beyond my estimations. It was so popular !
Time Pilot is a nice game to play and seems that lot of people are linked to the past, feel nostalgia so they want and like the game.
Ok !…truth is that Moon Patrol is a landmark for many people of our generation. I hope I won’t disappoint Moon Patrol’s fans 🙂

vector patrol_screen01vector patrol_screen02

– I haven’t seen such a Moon Patrol’s faithful port to any home system !

– Thank you again ! 🙂

Vector Patrol (Moon Patrol) Vectrex Homebrew Game Prototype Demo by geekwithsocialskills

– I own an original arcade pcb made by Williams

– Yes, I also have one…

– …in a side to side comparison they both play, sound and look like twin brothers ! Game play, graphics and music are all arcade perfect ! Speaking of music and sound, how did you manage to compose the music theme ?

– For the music theme I’ve just listened to the original arcade. I had to make some sacrifices though. Vectrex has only one sound chip. It’s a General Instruments AY-3-8912. (AY-3-8910)

sound chip

A legendary sound chip with three sound channels and one for noise. If I remember correctly, the arcade board has two of them. It uses one of the two chips, (all three channels) for the background music during game play. I couldn’t do that in Vectrex because there wouldn’t be any more space for the sound effects like explosions or shooting…I reduced the music tune playing on only one (of the total three) channel. You may have noticed that music isn’t too fancy like the arcade but I did my best and I think that players will accept this. I used the other two channels for sound effects. Moon Patrol music tune wasn’t so difficult to compose, it is a bassline with some drum sounds, you can code it directly to assembler. The music player I use in my program isn’t any fancy .ym music player. I coded it myself, it’s a special optimized music player for this kind of tunes, a small but fast enough engine. I need speed because I have not much time to do some music updates during the main game loop.
Every time I want to compose .ym music for Vectrex, I use “Vortex Tracker II“. It’s a very nice tracker in Windows, tailored especially for the AY series chips like AY-3-8910, AY-3-8912 and for Atari YM2149, programmed by Sergey Bulba. You can download it online, even its source code to modify it according your needs. I’m not so great in composing music in trackers so this could take several weeks. I would also thank Der Luchs and Factor 6 for lending me their music for Vector Patrol !

– Have you any music background studies and knowledge ?

– I really love to make electronic music. I had some synthesizers as a teenager and I did compose some tunes but I never followed some special education or music studies. I spent a lot of time with my synths before I had the Vectrex console. I still have a Roland Alpha Juno-1 (JU-1) which is one of the last Roland’s analogue synths.


I really love to design new sounds on that one, it’s standing right behind me now. I love to experiment with audio and music. I had some sequencers. I made my very own synthesizer, well I made a keyboard from an old one, combined with a midi controller. I had a midi synthesizer module that I built into a big case so I considered this my own synth. I am not a good player actually. I made some music but I am very bad composer 🙂 I can’t read any notes on a paper but OK ! I can manage to find some chords, to replace some tunes but again I am not a good musician.

– Shall we expect some new stages and enemies as well ? ..Eastern eggs ? Could you please send us some fresh screenshots with the new stages/vehicles/enemies to share with our readers ?

– I think you refer to Vector Patrol. Well, I did my best to build in some extras, for sure. Some code memory is still available. I think that after Vector Pilot people expect some more. It’s not easy to merge some new ideas into an existing game play but there is some new, extra stuff in Vector Patrol, like new enemy types. There is a new type of enemy UFO, a big one that will take multiple shots to get it down. Its scale will be bigger, like the giant birds in Exerion and it will make a low pitched fluctuated sound. There are also some other, new UFOs like the mine throwers (that’s how I call them). I will keep their shape in secret 😉 . They will appear in later states, throwing magnetic mines. These mines will fall in a rotating way and they fall on to the ground with a dust impact but they don’t make a crater, they will remain still as the mines in the mine stage, so the player has to jump over them.

Vector Patrol_new enemies_1

Vector Patrol_new enemies_2
There will be some new player vehicles; they have to be earned like the ones in Vector Pilot. There will be two new vehicles. I think these are enough.
The first one will be an original lunar roving vehicle from the Apollo missions , right back from the ’70s.

   new vehiclesA new vehicle-type + appropriate base:  The apollo missions moon buggy and the LEM-module.

The last one…I don’t know if I can reveal it to you, but as a beta tester you will eventually find it. Well it will be a space cowboy, I real cowboy on a galloping horse ! The horse and the man on it will get up and down…I think it’s a nice animation…you will see it in the next beta version.

Vetor Patrol_Cowboy
As “courses”, we have the original beginner and champion course and we also have new courses. These two original courses will be completely the same as the original arcade. This one is the result of some reverse engineering. Every obstacle, every hole, every crater and every rolling stone has been timed exactly the same way as the original. There might be some differences between them but they will be reduced to a minimum.

As said before, there will be new courses as well, featuring these new enemy types. I have also added a new sign on the ground, not an enemy but a sign warning the player will encounter gravity disturbances. This was a bug that I discovered and I turn it to a new extra feature. It will be a zone in the new courses, some places with gravity disturbances. This means that when you jump with your vehicle, when you land on the ground you bounce a little bit back up, like in a low gravity environment, like having springs on your vehicle. This might increase the difficulty and challenging factor.

Vector Patrol_new enemies_3
These are all the new features already included in Vector Patrol.

–  How will its overlay look like ?

– I can send you some new screenshots with new vehicles, maybe one screenshot with the new stage and enemies.
I made some overlays, about one hundred of them during the previous printing run of Vector Patrol but I am afraid they are all totally useless. There is a design flaw. I drew a message bar, on the top of the screen which wasn’t properly done. My intension was to design a message bar, an overlay region in transparent color which would provide to the player info like the check point, the time and the progress bar from A to Z etc…The radar was also drawn there and some caution lights as well. Unfortunately this wasn’t working because it was on top, way too high and it wasn’t feasible enough to have a stable drawing of messages on that area on the overlay. These first series overlays are all for the waste, I think.
New overlays are like the old ones except the status bar flaw has being corrected.
The player’s buggy will be situated in a red painted area, surface will be green and first row of obstacles will be in green as well. Second row with all background mountains and flying saucers will be in blue. It will be a red area on top of that with all the high flying enemies in it. Those are all the main colors…red, green and blue. I think is a nice combination.

I’ve also made a limited run of overlays with a pink painted playfield. This is like the original’s arcade beginner course. Your buggy is pink in beginner course while is red in champion course. Pink instead of red color of player’s zone is the only difference between the two overlay versions.

– Many of modern gamers and young programmers don’t know anything for the past. Is it advisable for them to take a look behind ? I mean will you encourage youngsters to know and learn from the past ? Will you encourage other eager programmers to give Vectrex a try and join the scene ?

– Well…I know that many young programmers are also players. They do look to the past, playing old games but in a different environment, in Java or even in their smart phones. I suggest that they should take a look behind, to these good days that resources were so limited but game play was so good. That’s the reason we all loved these games. They were uncomplicated, so easy to use and easy to pick up and start playing with them…Youngsters could benefit and learn a lot from the past.
If I encourage other programmers to join the scene ? Why not ? If they are interested in this…Yes !
Vectrex is a very unique console, it is the only vector based home console out there…ever! So why to not encourage them ? Why not ? It will be nice to have some more activity to the Vectrex programming scene. Definitely yes !

– Would you like to share some funny or frustrating moments during development (If any…) ? (Hard disk and computer failures, cats walking on keyboards, parrot chewing your listings 😉 etc, etc…..)

– I haven’t any pets in house so I am not involved to this kind of events 🙂

My greatest frustrating moment was some years ago. I had an usb stick crashed. It wasn’t for Vector Pilot, its code was nearly finished and stored safe in another usb stick I had…it was…believe me George on that…some reverse engineering I was doing on Exerion and all my work done so far, gone ! All this disassembled code gone ! I couldn’t recover it and I didn’t take any backup. I was so angry with myself ! I had disassembled a big part of code, I was quite far with the reverse engineering process and everything lost, so I have to redo it again..OK !…That’s lesson number one. I now use only usb sticks of 1 GB …only ! It’s a single level memory cell technology and they almost don’t crash. I don’t want 2 GB or more because they are based on multi level memory cells and apparently I had very bad experience with that. The usb stick that crashed was 8 GB and yes…it crashed !
You are always getting funny or hilarious moments during the development phase of a game. Game play is often completely different from the one it should be. For example with Vector Pilot there was a bug, making the player’s vessel flying backwards !…it was actually funny watching your vessel flying backwards. I turned it to an extra feature and it is hidden in the game. You can activate this reverse flying mode in a hidden menu. I had also another bug with bullets not being shot from the nose but from the rear of your plane. That’s the tail gunner mode now.
Another bug I found in Vector Pilot which is not implemented as extra feature because is so sadistic 🙂 …The player was capable to shoot all parachutes that were falling. You could shoot them and they were exploding 🙂 …it was so funny…not to capture them but actually kill them 🙂
I did some funny programming in Vector Patrol too. I designed a space cowboy as an extra player – vehicle. When the horse crashes to a rock or an obstacle, you can see its legs flying and then drop to the ground the same way that the moon patrol vehicle crashes and its wheels flying in the air after the explosion…it’s quite a hilarious animation!
That’s all I can tell you so far. I don’t know what else I will find out during Vector Patrol development…

– Are Vectrexians and Vector Pilot still available for sale through your site ?

– Yes, they are both still available. I have recently produced a new batch of overlays for Vectrexians and Vector Pilot as well, so I think I replenished my stock more than enough.

Vectrexians_Box  Vector Pilot_Box

– What if a title eventually sells out ?

– I never did a limited release or something. As far as the customers’ demands I will produce more carts, boxes and overlays. My silkscreen printer guy is on retirement now, so I have to find another resource but again my games’ stock will be sufficient for years. There is not any problem with that.

– Will you start the production again making some more copies or leave it to raise a collector’s value ?

– No ! Once again I don’t want to make limited runs. I will continue to produce my games as long as I can, to help more people acquire them. I really want that people play my games not collecting them and put them in closets or cupboards and resell them. No, that’s not my intention, definitely not.

– My opinion is that both your games (and I am referring to your future releases too) have a high desire factor and collector’s value. Could you imagine their prices on Ebay some years after a “Sold Out” ?

– Yes…I am aware of some auctions on Ebay for Vector Pilot. One of them went way too high…250$ or 300$…it was amazing, even crazy because people apparently don’t know that my games are still available in Europe. They can buy them for 40 Euros that is something of 50$. Giving 300$…it’s really crazy!…but ok, that’s a free market, eh ?
If they really sold out? Oh, then I don’t know what the price will be…

– Shall I put my copies deep into a treasure chest or a safe ? 😛 🙂

– Please George…don’t ! Play them ! That’s the reason they are made. This is the reason that the overlays are made. Play them ! That’s the greatest satisfaction I get from the buyers…They play them ! Really !

– Does your son enjoy playing your games as both my sons do ? 😉 …

– That’s very nice to hear 😉 …

kids playing vectrexiansMy little ones play Vectrexians, their favourite !

– What is his high score ?…

– My son is more into the Nintendo 3DS but sometimes I force him to take a look to Vectrex. He is only 7 years old, maybe not at the appropriate age to play Vectrexians or Vector Patrol but he likes it. His favorite game was Clean Sweep but again I think that his generation is more for games made for Nintendo 3DS. I own four Vectrex consoles, so anytime he wants one, he can get one for sure. I also put him as a game beta tester sometimes…to do some monkey testing 🙂

– “Vectrexians” are my kids’ favorite ! Mine is “Vector Pilot”.
😉 I even made my own arcade style joystick to enjoy it at its full glory !

– That’s very nice to hear George ! So you made your own joystick…Concerning the Vectrex joystick itself, I think that the swing is too long for some games like Vector Pilot. It takes too much time going from left to right. It’s nice to hear you made an arcade joystick and I hope you are getting good experience with it, playing Vector Pilot !

Vectrex Arcade Controller 2

– I would like to THANK you very much from the deep of my heart !

– You’re welcome George !

– Would you like to say something else, I forgot to mention, to our readers ?

– Well George… Let’s say by myself here in Belgium I wish a happy New Year to you and your readers. Thanks for the interview and for your interest to Vectrex and to my games. Vectrex is so nice and unique console. It deserves a good place into the gaming world not only in the past but also into present. It still lives… it’s very nice that new games come out and people talking about these releases…Vectrex really deserves its place !
All my best to all my Greek colleagues, wish them lot of game play !
I also hope that everything will get improved in Greece economically wise. Things aren’t too good here in Belgium either, and for the rest of Europe as well but I do know that situation in Greece is critical. I hope you will find a way out…
Let’s keep on playing Vectrex ! We will keep in touch with Exerion and of course with Vector Patrol. Testing is not finished yet. I know how important Exerion is for you George. It’s also important for me, believe me and I will make a lot of work with it 😉 Don’t forget you will need a lot of patience with me…work, family life, so many things to do and so little time 😉

– Thanks again for your time Kristof !

– Thanks for this interview… I will see you around ! Bye !



I am an avid collector of retro hardware. I collect anything retro ... from calculators, to real arcade boards and home computers. Being a tech/craftsman (self taught by experience), I like tinkering with electronics. I believe that hardware engineering is a kind of an art form. I don't want to miss any chance to grab my trusty screwdriver and my precious soldering iron just to repair, improve or spice up with a ‘mod-flavor’ almost anything. I was familiar with retro scene world when...wasn’t retro at all (!)...

8 thoughts on “Kristof Tuts interview (English)

  • February 25, 2015 at 6:14 pm


    Α ρε ΓΙώργαρε! !!!!!!RESPECT!!!!! φίλε για την πολύ μακροσκελή και ΑΝΑΛΥΤΙΚΟΤΑΤΗ σνέντευξη… Διάβασα όλο το άρθρο με ΠΟΛΥ ΠΡΟΣΟΧΗ λέξη -λέξη….

    Απίθανο συναίσθημα να προγραμματίζεις σε Vectrex! O Kristof πρέπει να είναι πολ COOL τύπος και τον νοιώθω πραγματικά οταν αναφέρετε στα σναισθήματά του προγραμματίζοντας αυτόν τον ΘΡΥΛΟ της εποχής!


    Geoana σε ευχαριστώ και προσωπικά για αυτή την πολύ όμορφη συνέντευξη φίλε!…
    Με ταξίδεψες πραγματικά σε εποχές νοσταλγικές…μπροστά σε ενα μόνιτορ να γράφεις αμέτρητες γραμμές κώδικα !!!!

    Αυτό ειναι!!!!!!!!!!!!!!!!!!!!!!!!!!!

  • geoanas
    February 25, 2015 at 6:22 pm

    Έλα Alex !
    Σε ευχαριστώ για τα σχόλια σου…να ξέρεις ότι θα ακολουθήσουν πολλά και ενδιαφέροντα από Vectrex, Commodore και …. 😉

  • NiCkeD
    February 25, 2015 at 8:17 pm

    Επιτέλους το ”θηρίο” δημοσιεύθηκε! Για άλλη μια φορά μπράβο George! Πολύ ενδιαφέρουσα συνέντευξη, έμαθα αρκετά για ένα μηχάνημα με το οποίο δεν έχω επαφή!

  • nkary
    February 25, 2015 at 9:51 pm

    Very nice interview, it covered almost everything 😉
    It’s an honor for us, here in iamretro, to host this conference 🙂
    Thanks Kristof
    Thanks Geoanas

  • glaros
    February 26, 2015 at 12:43 am

    Απολαυστική συνέντευξη με πολλές πληροφορίες.

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