Phantom Slayer is a video game released by Med Systems Software in 1982 for the TRS-80 Color Computer and Dragon 32/64.

Written by Ken Kalish, Phantom Slayer has been cited as an early forerunner of the modern first-person shooter genre.

[1][2] The player moves around a randomly generated maze, attempting to kill the eponymous phantoms by shooting them.

As each level is cleared, a new maze is created, and the phantoms became harder (requiring more shots) to kill.

Combined with their creepy ability to get in close and blind-side the player, this is effective for elevating the fear factor.