I have a 128dcr with u1541-ii cartridge and 1902a monitor. I'm writing an adventure interpreter/mini vm. works on 64bit linux and c64/128. right now its scott adams level verb/noun but i'm expanding it to use some little more complex stuff but not fullsentence (ie: you can say unlock wooden door with wooden key.. it cheats and you get {player} verb noun noun.
game script compiler is actually a ruby script so you cant compile on the c64/c128

but the binary data files are transportable between systems, so too save files...