I greatly appreciate all the support , but this code has yet to prove itself conclusively of being able to go the distance as far as the full game is concerned. With the demo almost finished (which it may remain for a long time) I've got a lot of other things to look into before trying to proceed. I'm feeling atm that Blitz is better geared towards programs where the entirety of the graphics etc. reside in memory. Blitz coding is a double edged sword, you get all sorts of help with setting up the environment and getting things running – and finding sources and examples is pure gold (the manual is always not very helpful). But to try anything not well documented/sourced is a slog – you are in an environment where you can use ASM but the integration with the Blitz semi 'fire and forget' methods requires knowledge a step up (or down, strictly speaking) from what BASIC programmers are used to. It remains however a great environment to tinker with ASM.
Sokolovic – I'll send you a link, but we're very close to just putting this out now, warts and all.