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Title design by Rob Smith

Now on YouTube


During the latter part of 2016, I was considering fulfilling a childhood dream of writing a computer game for one of the 8-bit computers; based on nostalgia I’d connected with them. Gone were the playground disagreements regarding the Spectrum and Commodore, as I’d had both and appreciated them for their part in the early part of my life.


This aspiration suddenly gained momentum when I watched a YouTube video posted by Techmoan on the 5th October 2016, which discussed the journey Mat had taken fixing two Commodore Executive SX-64’s. Having watch the video several times, I was surprised that despite growing up in the 80’s and owning a few Commodore’s; I’d never heard of the SX-64. Mat had made the decision for me, I was going to learn the Commodore 64 architecture and write a game that broke existing boundaries.


Whilst researching the Commodore 64, I also identified many additional models that I was not aware; such as the Commodore 128D, the Commodore 128DCR and Compucase 64D case which housed one regular Commodore 64 and two 1541 disk drives. I bought every variant of the Commodore 64 or 128 computer, starting with one of the SX-64’s advertised on eBay that was in Techmoan’s YouTube video. 


Throughout my spare time since 2017, I studied the Commodore 64’s architecture (6510), its assembly language (6502) and the Commodore Video Interface Chip, commonly known as the VIC chip to identify efficiencies and short-cuts to achieve my goal.


At the beginning of 2018, I was ready to code my game, without a game design or knowledge of the tools required to write a Commodore 64 game. Fortunately, I discovered CMB prg Studio, a Commodore development platform for the PC written by Arthur Jordison; which enabled cross-platform development.


Having gained confidence with my 6502 coding competence, my first Commodore programs became procedures and key gaming routines; which enabled me to understand performance, graphics, interrupts and timing restrictions of the Commodore 64 – but also how to counter these restrictions and develop short-cuts to truly open-up the Commodore 64 .


I have now spent (on and off) over a year writing a defender style game which has a fast parallax landscape and sprites in both the top and bottom borders (so using the entire vertical screen); totaling a maximum of 40 flicker free screen sprites per raster refresh.


Although my coding graphics skills are now maturing, my ability to write music scores using the Commodore’s sound interface device (also known as SID) is poor. As a result, I contacted numerous SID artists from the 80’s over the past year and have managed to cement a gentleman’s agreement with Kamil Wolnikowski; better recognised amongst Commodore 64 ‘demosceners’ as Jammer.


Kamil has kindly agreed to write an exclusive SID track for the Space Walkers title menu, on condition that the game once completed is free to download – which it will be. In the interim, Kamil has kindly allowed me to use his 2005 SID score (which I found on GoatTracker) called ”My Own Hyperspace”; which is an excellent track.


I’m aiming to complete the game before the end of 2019, so outside of being a dad and managing a career; I think I need to put some more hours in! 

If you would like an introduction to Commodore 64 assembly programming, send me an email and we'll go from there.


Please include your current ability [none, novice, intermediate] and we'll see what we can do. 

All the best,


Mark Heslop


Key Commodore configurations and Space Walkers design and ideas.

Space Walkers Game Screen.jpeg
Commodore Kernal Functions
Kernall Routines.jpg
Space walkers memory configuration
Memory Map.jpg
Space walkers Raster configuration
Space walkers parallax design
Parallax setup.jpg
Commodore 64 Memory Configuration
Commodore 64 Memory Configuration.jpeg
COmmodore 64 memory configuration
RAM Setup.jpg
Space walkers theme configuration
Colour themes.jpeg
Space walkers border sprite design
Bottom border sprite.jpg
Alien Idea.jpg
Early Periodic Table Idea.jpeg
Early Periodic Table Idea3.jpg
Early Periodic Table Idea2.jpg
Space Walkers landscape2.jpeg
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