Dungeon was one of the earliest role-playing video games, running on PDP-10 mainframe computers manufactured by Digital Equipment Corporation.
Players chose what actions to take in combat and where to move each character in the party, which made the game very slow to play by today's standards.
Daglow wrote in 1988, "In the mid-seventies I had a fully functioning fantasy role-playing game on the PDP-10, with both ranged and melee combat, lines of sight, auto-mapping and NPC's with discrete AI.
Its use of computer graphics consisted of top-down dungeon maps that showed the portions of the playfield the party had seen, allowing for light or darkness, the different "infravision" abilities of elves, dwarves, etc.
[3] A third game called Dungeon was released on PLATO in 1975, by John Daleske, Gary Fritz, Jan Good, Bill Gammel, and Mark Nakada.