If you've watched the commercials you pretty much have an idea what you're in for. If you enjoyed the first one, you're in for a treat because it's actually a little bit better. The visuals are alternately hilarious and gross and the violence is ridiculously over the top, but it's done in just the right way. It's almost like watching a live action loony toons cartoon. This movie could have turned out very badly, but I was impressed that they actually came up with a movie that kept the same goofy concept and actually cranked it up a notch without becoming totally absurd.
So, yeah, good movie, I enjoyed it. It's not for everyone, but it's very fun if it is.