I just beat the single player and yes it is good. It is as short as the first one and there is no amazing twist in it like the first but it is still worth playing.
My gf loved the first one and got part 2 last week. Needless to say, she loves this too. I don't have much interest in the game but I gave the multiplayer aspect a try and really dug it. It's kinda like Halo with superpowers.