Bioshock 2 begins as a serviceable shooter in a world you already know if you played the first game. Be prepared for a little bit of early disappointment. "Oh, this again?" you might ask after an hour or so. "I've already been here. I've played this game before."

You have no idea.

Read the spoiler-free review after the jump.

The first Bioshock revealed Rapture, an underwater city founded on the principles of enlightened self-interest, free of moral, religious, or political constraints. As happens to most utopias, it failed horribly. Rapture fell into chaos during a power struggle between its founder, Andrew Ryan, and a profiteer named Frank Fontaine. Both men were eventually killed by the same assassin.

And if there's one thing that hates a vacuum worse than nature, it's a deep sea environment. So Bioshock 2 reveals what happened after Ryan and Fontaine were killed. Who took over? And how do you fit in? What's your place in this aftermath? Whereas Bioshock was a brainy idea-oriented story about identity and free will, Bioshock 2 is a powerfully personal story about, well, parenthood. It's the shooter equivalent of a nasty custody battle.

You probably already know that you play as a Big Daddy. If you didn't know that, you would have found out in the first five seconds of the game. You're staring out of a Big Daddy's helmet as you draw near one of those unmistakable art deco vents into which the Little Sisters retreat. As you get closer, the oval of your facemask fills with the dark circle of the vent. For a very brief moment, it's like an eye, starting back at you. In a way, this is the message of Bioshock 2. You are being watched and what you do will matter. Pay attention to the first vent you come across when the actual gameplay starts. Did you see that pair of tiny blinking eyes? It's not just a nifty detail.

As a shooter, Bioshock 2 has come a long way. The new developers at 2K Marin have clearly put a lot of work into improving the combat sandbox formula. Battles that can unfold a variety of different ways can now unfold in more ways. There are new weapons and powers, and a couple of new enemies. But the developers didn't stop there. Because Bioshock was partly a meditation on free will, there was a delicious irony to the fact that it mostly shunted you through corridors. Fair enough. But that's not the case here. Each section is mostly wide-open and wonderfully non-linear. Rapture is built from active arenas rather than hallways to be cleared. Your decisions about how and when to upgrade your powers and weapons are a crucial part of how the game will play.

And because you're a Big Daddy, the Little Sisters aren't just collectibles for an occasional resource boost. They are your charges. They provide an important through-line for the story and the game progression. They give Bioshock 2 a delicacy and a certain amount of sadness. But some of them are no longer delicate, sad, or little. Big Sisters are Rapture's greatest threat. Fast, armored, sleek whirling dervishes flinging fire, lighting, and furniture, preceded by an unmistakable iconic shriek. Here is the real payoff for setting this game ten years later than the original. Last I saw you, girl, you were barely knee high to a grasshopper, and now you're bouncing off the walls, throwing plasmids, and kicking my ass. What a difference a decade makes.

As with the original Bioshock, it's going to be a while before you fully understand where you are and what you're seeing. If you recall your disappointment at how the first game wound down, rest assured that won't be the case here. This is a lot of the beauty of Bioshock 2. It's full of its own surprises, twists, and reveals. It's no mere retread. Like all the best sequels, it is its own game, with its own perspective, its own themes, its own gameplay. And like the original, it goes from being a fantastic shooter to an astonishing and poignant revelation that videogames can have powerful, relevant, memorable stories.

Later this week:
Tuesday: 10 times I fell in love with Bioshock 2
Wednesday: helpful tips from the other side of the game
Thursday: the multiplayer review
Friday: a conversation with the developer