I took a look through the BAS source file - it doesn't appear to be QBASIC source. If it was compiled with QB64 (which it seems to be) then it's not a DOS compatible binary, it'll be a 64-bit PE so unfortunately only runnable on a 64-bit version of Windows.

OP says that they've been at it for decades so my guess would be it started as a QBASIC game but then was later ported over to use QB64 and its modern features.

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kqr 4 days ago | parent [-]

Strange. The web page mentions it being runnable in DOSBox for non-Windows platforms, but I suppose the author might not have tried that in a while...

	▲	rep_lodsb 3 days ago \| parent [-]
		I've looked at the EXE file, and it's supposed to print "This program cannot be run in DOS mode." when run under (real or emulated) DOS. The reason why it fails to do that is that the compiler did not set the memory allocation fields in the header correctly, so the stack is either overwriting random memory or may be somewhere that isn't writable at all! Apparently nobody tests this stub code anymore, might as well leave it out completely... (maybe Windows even accepts files that start with the PE header instead of MZ?)