Never heard of Bioshock before? Perhaps this will whet your appetite...

So you've seen the guns and gore... but what is Bioshock about?
BioShock is a unique game that mixes a spine-chilling setting illustrated with art deco art and architecture, sci-fi themes of bio-genetic mutation and self-modification, a deep storyline with open-choice freedom to interact with the world as you choose, and first-person action that requires you to think every time you pull the trigger. After your plane crashes into icy uncharted waters, you discover a rusted bathysphere and descend into Rapture, a city hidden beneath the sea. Constructed as an idealistic society for a hand picked group of scientists, artists and industrialists, the idealism is no more. Now the city is littered with corpses, wildly powerful guardians roam the corridors as little girls loot the dead, and genetically mutated citizens ambush you at every turn.