Bioshock got me interested from it's trailer. Got it last christmas on 2007. And I had to say, it's a well-done masterpiece. The gameplay has RPG elements with all those exhilarating exploration of the atmospheric world of Rapture, picking up all those weapons, E.V.E. and food and drugs (which basically increase your health or your Plasmid level). 

It has some fun puzzles and a minigame (involving pipes) to have fun with. The atmosphere of Bioshock is amazing and a true feel to the 20th century along with those shadow effects to keep it very creepy. The plasmids select a variety of fun to the game such as telekinesis (like Half-Life 2's gravity gun), ice, hornets, fire and more. The story is very interesting that you have to solve the mystery yourself with all those diaries and characters explaining it to you. Weapon upgrading is now something original to gaming history, allowing you to upgrade your gun with more powerful handling with enemies.

 The game can have technical issues all around the game. Now, time to talk about the Big Daddy (not Rosie). He's a very awesome sub-boss of how he impales those guys with his drill and how he roams the halls of Rapture with those Little Sisters. The Little Sisters, on the other hand, are cute but a little ugly. I mostly rescued them, because it feels of actually killing a child (if you harvest them). So Bioshock is an atmospheric masterpiece under the sea.