Incredible game!
The setting where the game takes place, Rapture, is one of the coolest and spooky places I've ever played through. The game expertly shows you glimpses of what it once was, and through innovative narration describes how it slowly turned into what you see around. The citizens have devolved into super powered junkies who only care for their fix of ADAM, the main currency of the city. Hoarding the precious resource are the Little Sisters, who I admit looked innocent enough that not once it occurred to me to harvest them. And then you have the Big Daddies, the Little Sister's protectors, who roam the halls and make their presence known with their whale-like moans.
The weapons and magic (plasmids) options are phenomenal, bringing a good balance to attack. You can go all out and fight everyone head on, or you can take a stealthier approach, set traps, and pounce quietly on your opponents, making it a game you can replay to enjoy the journey in different ways.
The story is very well thought out, and the way it unfolds if very satisfying, driving you to continue your way into the mess that has become Rapture.
I was very satisfied with this game, and plan to replay it soon. If you haven't played it yet, you should have no excuse to pick it up, as the price is right, and the gameplay is good enough for first person shooter veterans and newcomers. I'll probably wait for the second one to drop its price so I can go back into Rapture.