System Shock 2

System Shock 2 is the 1999 sequel from Irrational Games and Looking Glass Studios that effectively built the immersive-sim horror template that Bioshock, Deus Ex and Prey would later inherit. You wake from cryosleep on the starship Von Braun to discover cybernetic implants grafted to your flesh, the crew slaughtered, the infected roaming the halls, and a familiar rogue artificial intelligence — SHODAN — taunting you over the ship's communications. The voice you remember from the original returns, and so does the question of whose will is actually guiding your hand.

The campaign opens with a choice of military branch — Marines, Navy or OSA — each granting different starting skills, weapon proficiencies and paranormal psionic powers. From there, you upgrade across improving hacking, weapon handling and psionic abilities, picking up the cryptic audio logs that survivors and victims left behind, encountering ghostly apparitions of the dead replaying their final moments, and conducting research on captured alien biological samples to unlock exotic weapons and items.

The horror works through deprivation. Ammunition is scarce, weapons degrade with use, save points are limited, and the infected — the Many, a flesh-based psychic hive mind that has consumed the crew — keep ahead of your ability to fight them off cleanly. The cooperative multiplayer mode (Windows-only) supports up to four players if you want to share the experience, but the central horror of being alone with SHODAN's commentary in a ship that knows you better than you know yourself is the version most players remember.