A strange little side quest
If Palisade Guardian sends you down a curiosity rabbit hole, start here. Doom changed game design and distribution in 1993 by separating its engine from content and spreading widely through shareware. Another piece of context lands nicely beside it: Midway's Gun Fight from 1975 was the first arcade video game to use a microprocessor. The details change, but the appeal of learning a system and trying again is remarkably persistent.