Catacombs 3D

This is supposed to be the first FPS ever made, its from 1991 and was made by the same people who later made Wolfenstein 3D (which was waaaaaaay better) and Doom Id Software (Quake, Doom, Wolfenstein, Rage) EDIT: There is actually a much earlier FPS game than this one. And it even has multiplayer: Thanks to tayumapower for making me aware of this