Great action game with RPG elements sprinkled on top.
Take an open world game with lots of good explosions and gameplay, add character progression and RPG elements, stir liberally and you get Crackdown. This is a great game that I continue to come back to every few months or so. It's easy to pick up and play, and jumping over and around buildings is fun.
I'm not a wordsmith, so all I can say is that this game is definitely worth the money and will provide several hours of fun.