Infamous 2 improves in every way possible, but it suffers from the same faults as the first. Minor Spoilers
After finishing as Good Cole and half way into Evil Cole on Infamous 2, I find it is bigger and better but ultimately falls short just like before. On the side mission "stronghold" the game always freezes for me. Turning on Flood Town's power froze for me 6 times on the 3rd generator. I've fallen through houses in Flood town as well as grab wires and suddenly be flung across the screen.
The first game was pretty good in obtaining powers and made you feel like a superhuman but not god. In this game, it gives you a task of defeating a monster of unimaginable power, yet the "powerups" you receive....don't really do much to combat him. I'll leave it at that to prevent spoilers..
Now lets talk about the most annoying factor of this game. Knockback. Play on hard (to obtain the trophy) and you're looking at black and white 90% of the time, enemies knock you back endlessly (think lost planet 2), and one rocket either kills you outright or leaves you with a sliver of health. It's beyond retarded. All I say is good luck with the Behemoth.
I do like the powers (although a bit underwhelming in terms of the story) and they did fix a few things, such as better side missions (still some that suck though. I'm looking at you photographer), even incorporated it into powerups, which are all useful so you're very inclined to do them (60 of them). At 60, you can get blast shard sense, which will point you in the right direction to the closest blast shard. THANK YOU FOR THIS!!
The UGC downright sucks, but I guess people need to experiment with it but you shouldn't publish crap missions. I lost interest in trying them out because people stick impossible scenarios in the first half of the first island.
Overall, I love the game just like the last, but I like games with at least some replayability. 2 playthroughs isn't considered that imo.