Games That Weren't 64

"Back in the mid to late 1980s (I think I was about 16 or 17), I answered an advert looking for a C64 programmer to do a software conversion of a Spectrum game called Deathstalker by Codemasters. I went on a day trip down to Hull to meet the programmer, Tony Warriner. He picked me up from Hull train station in a white Ford Escort and we took a drive over to the office to check out Deathstalker. I'd never played the game before, just seen screenshots.

Deathstalker was a 2D action adventure viewed side on. The unique selling point to Deathstalker was the way that certain sections of the screen were only visible when the character was within sight of them. For example, there could be a deep well or chasm onscreen, but the player wouldn't see the well or chasm until he'd walked fairly close to where it was and then it would flick on to the screen. I was a fairly accomplished programmer at this point and was quite happy to take on the conversion. I was furnished with all the graphics and maps for the Spectrum version so that I would have something graphical to work with during development.

Up until this point I'd been using an assembler for the 64 that worked by using line numbers so that the source code could be saved as if it was a BASIC listing. I can't actually the name of the assembler but it pretty crappy and should only really have been used for small demos and not full games. The code written on the crappy compiler would look something like this:

10 SEI

20 LDA #$78

30 STA $0314

Etc etc

This was fine initially, but when it got to the point of bug fixing and then having to insert extra code, that's when things started to get quite challenging. I remember spending a good deal of time re-numbering a lot of lines so that I could insert more code.

The game itself was starting to take shape, you could wander round the map, and the scenery that should disappear did disappear and reappear when appropriate and there were baddies that would react to your presence. Then it all went horribly wrong, one day I tried to do a compile of the code, but the listing was too big for the compiler and it crashed all the time with an out of memory error. I wish back then I had found out about Turbo Assembler. If I'd been using that, then a C64 version of Deathstalker may well have become reality."

Mark Gallagher.