Not available on the Internet, as far as I can tell; I uploaded the ASM source file for now. I have the com file too (from a 1990s CD-ROM backup), if anyone wants to backup this.

(And the winning move is not to play. Just don't touch any (shift) keys and fall through the abyss :)

@tomaes: well it is now. uploaded the complete package. did not know that this one was missing so thanks for pointing it out :)

\o/