From the PlanetXbox360.com feature review:
"Mitigating transition, Bioshock 2 is immediately familiar, with some minor changes. Picking up 10 years from the original, Rapture is still deteriorating from the oppressive rule under a new dictator, the Communist Sofia Lamb who offsets Ryan's Objectivism, and the incessant hunting of ADAM for diabolic intent. You play as the original Big Daddy and your motivations are the same the original protagonist: protect the weak and punish the large, only now it is personal (Like all good sequels, the stakes are higher and the brawls is bigger). Mechanics are familiar; you rummage in trash for abundant consumables, fight splicers, obtain plot developments and dialogue through radio and melt icy obstacles,and shock faulty electronics with Plasmids. Bioshock 2 does vary from the original, but heightens the best parts."