AgentBirdnest: I briefly tried 2, but don't remember it at all. I think I started playing The Witcher 2 at the same time, and that ended up sucking up all my game time for a couple weeks :-p
Now that I think about it, I should try 2 again, rather than the first game...
I played some of 2 on co-op, but it was another case of multiplayer burnout.
Assuming I can get past the level I got stuck on, I should be through with the first one in a couple days.
Hate going backwards in a series, it always feels like the previous entry or entries get an unfair view because I get used to the improvements of a sequel.
For you it's different since you've beaten the first one. From what I remember, the second is also good.
More variety, a different playable character (unless I'm misremembering and that's co-op only crap), stuff like that.
Groaning a bit since I found out recently that they're taking the next game in the series and turning it into a League of Legends-type MOBA multiplayer thing.