System Shock

This innovative title from 1994 is a first-person sci-fi/horror game set aboard the Citadel space station, where the player has to fight mutants and robots created by the evil, yet brilliant, artificial intelligence called SHODAN. The game could look like any other first person shooter at first sight, but its detailed environments, engrossing story-line and one of the creepiest villains ever makes it a true classic which inspired games like Deus Ex and Half-Life.

A sequel, simply called System Shock 2, was developed by Irrational Games and Looking Glass and released in 1999.