> could you hazard a guess at what dialect this very old Forth game from Byte magazine was written in?
The writeup identifies the original Forth source/version as most likely FIGForth '78, so I assume that's correct. This doesn't mean it has no code borrowed from elsewhere, and we might never sort that out.
I should add that Forth has the property that you go from nothing to writing programs pretty quickly, because it's all based on RPN (like HP calculators) and there's very little infrastructure required to create a usable environment -- unlike virtually every other language I've created/used.
My having been a fan of HP calculators beforehand played a part in getting me started with Forth -- RPN was an aspect of Forth I didn't have to learn before getting started.
Remember also that the 6502 (the Apple II processor) had a rather easily understood assembly instruction set, which meant any adept 6502 programmer could basically decode and grab other people's work without needing a source listing. No longer true for modern processors.
Guess how we updated each other during program development and updates? Ready? 5 1/4 inch floppy disks stuffed into big manila envelopes, then snail-mailed. No, not making this up.