I know this is nitpicky, but I feel like this is the first maze game, and it's a different (related, definitely a predecessor) genre to the first-person shooter

I know this is nitpicky, but I feel like this is the first maze game, and it's a different (related, definitely a predecessor) genre to the first-person shooter. The big distinction in my mind is that a maze game locks the player into a fixed position and view in the maze and movement is made by advancing along this grid, while an FPS allows for free roaming. Maze games, while earlier than FPSs, and definitely an influence, went an entirely different direction, and remain a parallel genre to the FPS genre (see Legend of Grimrock). I think it's as important a distinction as other first-person genres like in-the-car driving game, in-the-cockpit space shooter, and flight simulators -- which are also not in the FPS genre, but feature things like a first-person perspective. Maze games also consist of your normal first-person dungeon crawler (lots and lots of D&D type games), MIDI maze and so on. Just like the distinction we make in genres between FPSs and Third Person Shooters (Tomb Raider, etc.). There's also a Third Person maze games (Xybots). I'm not entirely sure what the first FPS was, but somebody else here mentioned the Eidolon, that might be it. It most definitely wasn't Wolfenstein 3D (id even had an earlier games: Hovertank 3D and Catacomb 3D).