I've played a good amount of the first one and enjoyed it. What's wrong with the second?
Where do I begin: the story isn't even passable, the character was written by 13 y.o. who thinks that a good edgy character needs to cuss every two words, the V.A. is mostly ok but the main character is terrible, everything that was fun in Prototype was removed or changed.
The new enemies and powers kinda make up for it and if mindless distruction is what you want that's what you'll get but don't expect it to be as solid as the first one.
Edit: Heh, seems like now I'm on the other side of people being too harsh with a game
It's just that the first game actually had plot development and Mercer was a character that no matter if you liked him or not you could understand his reasoning and his goal behind his actions. James just has a goal and nothing besides it, the game could be half as long and it wouldn't change drastically. The powers seemed to have a greater difference between them and more importantly a role while in Prototype 2 you'll end up using the one you like the most/feel more comfortable because at the end they'll be pretty similar with the exception of 1.