A worthy sequel. Visually and mechanically a step up from the original Bioshock, though the story is a bit too convoluted for it's own good. The combat is notably improved and sticking splicers to a wall with a speargun is immensely satisfying. The city of Rapture is more colorful and feels larger thanks to the giant windows and the walks on the bottom of the ocean. It does come off as a bit more “gamey”; there are abundant set pieces and it's quite clear where one level ends and the next begins. The addition of guarding a Little Sister as she harvests Adam from a dead body is novel at first but wears thin after the third or fourth time. Then you have to do it about a dozen more... That's this game in a nutshell. If you liked the first game it's a safe bet you'll like this sequel as well, but the “been there, done that” feeling does set in before long.
The DLC (Minerva's Den) is not a bad crash course into Rapture, either. It crashed on me a couple times and I had to disable DirectX 10 effects in order to get through it. The noticeable visual downgrade didn't do it any favors. Still entertaining, however, even if it feels like a disconnected story that happens to take place in the Bioshock environment rather than anything essential. The ion cannon and singularity plasmid are highlights. My main complaint (besides the crashing) is the muddy objectives which lead to feeling like you're a rat in a maze at times. If you can get it rather cheap and aren't burned out on the series it's certainly worth checking out.