Z-machine

The home computer market of 1979 was a dozen incompatible machines, and Zork had been written for a mainframe. Joel Berez and Marc Blank solved it by compiling the game to bytecode for an imaginary computer with its own memory layout, dictionary and text compression. Each new platform only needed an interpreter; the story file itself was identical everywhere. It's the same pitch Java would market sixteen years later.

The format went through eight versions — version 3 carried most of the classics, and version 6 even added graphics. After Infocom folded, hobbyists reverse-engineered the machine, and Graham Nelson's Inform compiler (1993) turned it into a live target again. New text adventures still ship as Z-code and run in interpreters like Frotz, on hardware Infocom never heard of.