While its date of completion is not certain, but is estimated to be around 1974-1975, Maze War is considered to be the earliest mainframe computer game with a first-person perspective and one of the earliest to have network play, in-game chat, and a level editor. Originally released for mainframe computers, the game was not available on any home personal computers until the 80s, though it was available on the office microcomputer Xerox Alto in 1979: Video of Maze War being played on two Xerox Alto machines.
Gameplay is simple by later standards. Players wander around a maze, being capable of moving backward or forwards, turning right or left in 90-degree increments, and peeking through doorways. The game also uses simple grid-based movement, where the player moves from square to square. Other players are seen as eyeballs. When a player sees another player, they can attack them. While the movement was limited, the ability to move around in a first-person view was an innovation that set it apart from the more well known first-person light-gun shooters at the time where the player was always static.
The game's influence was most apparent in the role-playing genre, particularly early dungeon crawlers such as Moria, Wizardry, and Ultima, which utilized a similar first-person view along with tile-based movement and 90-degree rotations. In turn, first-person role-playing games influenced what would later become known as the first-person shooter genre.
A similar game was available on Atari home computers in the mid 80s, titled MIDI Maze, as it used the MIDI protocol and the machine's built in MIDI ports as a means of network communication.