2008-09-22 (updated 2008-09-22)
For the Imlac PDS-1.
Note that this game's creation and existence are undocumented. The source code was thrown away, it was encrypted anyhow, the binary probably does not exist anymore. However, the game was ported to other systems and those source codes are preserved. Those ports are also better documented. The information comes from Steve Colley's memory. He does not remember if it was Palmer or Thompson who suggested that shooting be added. Knowing when networks for Imlacs were available would possible narrow down the date of this game. He created a networked version for two and later more players to see and shoot at each other in the maze.

This game is possibly the world's first 3D 1st-person-shooter. A real 3D maze, where the walls closest to the player obscured the walls behind them. Players would raom the maze and try and shoot each other. Amazingly this was done on a CPU that had no multiply or divide operations.

Still further back, there are rumors of a game called SOLAR, a 3D multi-user 1st-person-shooter space warfare game from 1972 that ran on a Burroughs B6700. Totally undocumented.