: Wolfenstein 3D was the first real-time raycasting game. The earliest
: running-through-passages-shooting-things game I'm aware of was Maze Wars.
: Many RPGs were in first-person perspective before Wolf (Bard's Quest
: springs to mind), but consisted of bitmap images made into static displays
: (the only game like this for the Mac that I know of is Realmz in 3D
: dungeon mode).
Ultima Underworld WAS a first-person raycasting game, released in '89 I believe. The engine was actually a good deal more advanced then Wolf's or PID's, as it allowed for sloped floors. It was more akin to the later BUILD engine that powered Duke Nukem. Sadly it seems to have been forgotten by the masses. You kind find a copy of the game(PC only) on the issue of PCGamer with the full copies of ancient games that was put out a few months ago.