Leave the first game behind.
The biggest problem with this game is it is hard to not compare to it's predecessor. If you can block out the first and totally judge this game on it's own merit then this game is really good but it is not as good as the first. The story is good but the characters aren't as compelling and that is my biggest complaint when comparing to the first. Everything you remember about the first is there, similar levels, plasmids, weapons, and enemies. With the most notable addition being the big sisters which are probably the closest thing I remember to fighting a "boss". Although there wasn't a true boss in my opinion the overall difficulty seemed to be a little more difficult than the first. The atmosphere is classic Bioshock which is fantastic and the biggest draw for both games. I could literally spend hours just exploring Rapture and finding out about it's history. I was apparently one of the few fans of the first that actually thought this would be a good game but even I was caught off guard at how good the multiplayer is. The maps are fun, the weapons are fairly well ballanced and the surprises and traps around the map make this one of the most pleasant surprises I have experienced in a video game in quite some time. If you were a fan of the first then you should give this a shot and even if you didn't like the first try this one because it is different enough that it might surprise you.