Old machines had so little power you were forced into writing highly-optimised assembler if you wanted anything to fit into that tiny memory, or execute reasonably fast on those slow processors. Luckily, modern machines make the process of writing software so easy you can spend all your development time on the fun parts - and it's this part we'll focus upon. Starting with the game design, we begin by creating "Hello world" on the obsolete machine, understand the truly minimal requirements, and building up the game piece by piece.

We also touch on the issues of emulation, licenses, and publishing, given that the original Spectrum game has now been ported to the ZX81 for a commercial (and yet still open) release.