I have uploaded a new version of the game that you can try to compile on your c64. I have added constants for the screen width that you need to set. Let me know if you get it to run.
Sad news. I either don't have a C64 old enough to use the CP/M cartridge or the cartridge itself is bad. I tried it on 5 different breadbins, a C64C and even a C64U. On one of the breadbins I had some action from the cartridge after loading the disk but never got to the CP/M screen. I think I sold my oldest C64 a couple years ago. Maybe I will see if it will run on one of my Commodore 128 machines instead. Alternately I'll figure out how to load it on my Osborne 1. That would be cool.
Yeah, that’s definitely bad news about the CP/M cartridge. Sounds like you really gave it a thorough test across a whole lineup of machines, too. At that point it does seem pretty likely the cartridge itself is the culprit.
On the bright side, it really sounds like you’ve got an impressive retro collection there—five breadbins, a C64C, a C64U… that’s seriously cool.
Trying it on a Commodore 128 makes a lot of sense, and honestly the Osborne 1 would be a great option as well. That one especially feels like a natural fit for CP/M, so it’d be fun to see it running there if you can get it set up.