BioShock 2's story, set 10 years after the events of the first game, presents a Rapture in an even greater state of decline. Andrew Ryan is no longer in charge, but the city is still filled with wandering Big Daddies, splicers, and power-hungry humans. The game retcons in a few new characters, puts you in the roll of one of the original Big Daddies, and then sets you out to reunite with the Little Sister taken from you by central antagonist Sophia Lamb. Through audio diaries, you learn that Lamb has been stealing young girls from the surface to replace the ADAM harvesters that were rescued (or harvested; either way, the ones "taken care of") in the first game.
Yet despite the changes, you definitely get a strong feeling of the familiar as you make your way through the game. Not just in the look, but in the order that events unfolds. You'll find Plasmid powers in about the same sequence as the first game, and all the familiar ones have returned. Even though you're walking around in a huge metal suit with a drill for an arm, you don't actually feel like a lumbering giant -- you move like a normal, gun-toting human. The weapons are standard-fare from the first game, though modified aesthetically to fit your new Big Daddy physique.
Like Andrew Ryan in the last game, Sophia Lamb's disembodied voice haunts the halls as you wander through the city. You meet up with a seemingly untrustworthy "friend" who's also trying to escape. To make it through each area and onto the next, you have to get rid of one of Sophia's spliced-up cronies. Even the fetch quests and unlocking sequences feel overly familiar.