In any case the 8-bit-micro maze games are all handily predated by https://en.wikipedia.org/wiki/Maze_War https://en.wikipedia.org/wiki/Maze_War , which unlike

In any case the 8-bit-micro maze games are all handily predated by https://en.wikipedia.org/wiki/Maze_War https://en.wikipedia.org/wiki/Maze_War , which unlike all of them (AFAIK) is also a head-to-head multiplayer shooter with netplay, a much more direct precedent for the ID and post-ID FPSes. The thing that's underpraised about 3D Monster Maze is the quality of the writing and art. It's an (AFAICT) pretty unusual early highpoint of comic storytelling in computer games, which in some ways makes it as much the forerunner of Portal as anything else.