This seems like a really impressive effort to make sense of all this! Would the original game have been written in assembly? And if so, would the source have looked similar to this? Having never touched assembly language (aside from learning some very basic cracking many years ago swapping JE for JNE in the serial check routine, haha), it seems like a true dark art to me, so I’m really curious to know!
Yes, and probably somewhat. The programmers were Japanese, so variable names would almost certainly be different, and the assembler this code was written for is actually for the CPU in the Super Famicom/SNES, so although I'm not sure when the assembler was written, it certainly wasn't around in 1984 when this game was being written. I think that the notation style is based on Nintendo's system development documentation, though.
The NES would actually be a good place to look at some assembly, at least to get a basic idea of how it works. There aren't many operations, they're pretty easy to understand. There are only a few registers, and no layers of historic cruft layered on top ofit. The same (well, very close) CPU was used in a lot of computers from the same era: https://en.wikipedia.org/wiki/MOS_Technology_6502#Computers_...