Now, it's rare for a sequel to be as good as it's predecessor (more on that below), and sadly, that's the case here. That's not to say it's bad, far from it. It's got plenty of action, extreme graphic violence, swearing inappropriately and special effects. It just seems to lack some of the 'heart' of the first film.
Slipping into SPOLIERS territory here, I found myself enjoying the sub plot of Mindy trying to find out who she really is (and it's Hit Girl, obviously) better than the central 'I want to gather a team of super violent criminals to kill Kick Ass and burn down the city just because', and the Mindy side plot wasn't that great.
The cast did a fantastic job again, and Jim Carey was excellent for the few scenes he had (whatever he might be saying about the movie in the press), but far and away Hit Girl stole the show whenever she was butchering some bad guy for the hell of it.
Overall, a good movie, and if you enjoyed the first one it's definitely worth a watch. If you haven't seen the first one, go get it now and watch it, you won't be disappointed! (And if you really want to see something at the cinema, Alan Partridge is better, in my opinion.)
Now, onto films where the second film was better than the original (not the third film as in Army of Darkness or Iron Man 3 or series like Lord of the Rings where really it's just one extra long film)
Empire Strikes Back
Godfather part 2
Despicable Me 2 (saw it a few weeks ago with the children - amazing!)
Rambo (First Blood part 2)
Aliens (many may disagree with that one)
The Dark Knight
Spider Man 2
Star Trek 2 - The Wrath of Kahn
Dawn of the Dead (original)
Those are just from looking on my shelf, I'm sure there are many others, let me have your thoughts below!