BioShock is a first-person shooter and role-playing hybrid game, billed as the spiritual follow-up to System Shock 2, sharing many of the same developers.  BioShock is set in the underwater city of Rapture during 1960, although the city itself was built during the 1940s and thrived during the 50s.  Envisioned as an underwater capitalist paradise where the smartest and most cunning would rise to the top, the city soon falls into decay as the underclasses are provoked into a rebellion against the city's rule by Andrew Ryan, the businessman and philosopher who founded Rapture on the principle of the "Great Chain."

The player takes on the role of Jack, a silent protagonist, whose plane crashes in the middle of the Atlantic Ocean.  Jack quickly finds a lighthouse in the distance and makes his way inside, only to discover a bathysphere to Rapture.  Upon arrival, he finds the city in disrepair and its inhabitants almost entirely hostile.  At the behest of a friendly man named Atlas, the player will have to uncover the mysteries of Rapture, its downfall, and Jack himself, in order to escape the city.

Gameplay in BioShock can be best described as first-person shooter with RPG-like progression through the acquisition of new weapons and abilities, though there are no statistics to speak of.  Using Plasmids, Jack can upgrade his own genetic code and gain new abilities both used for puzzle-solving and fighting enemies.  Levels are relatively non-linear, though the path through the game is fixed, and exploration is just as big a part of gameplay as combat.  Like System Shock 2, audio diaries are scattered about the city which offer glimpses both into the lives of Rapture's citizens, and also into the ideas and situations of major characters in the story.