Basically what Zhukov said. FEAR 3 is really damn good in co-op as it's designed to be exactly that. It's not as scary as it should be in my opinion and the points system is really obstrusive to immersion in single player, but in co-op, when you are really actively competing against the one person you're supposed to rely on, it can get hectic and interesting.
Bulletstorm is, as Yahtzee said and I can confirm, torn between what it wants to be. You can see People Can Fly throwing in as much hilarious crap as one would expect from the Painkiller makers but it's weighted down by the out of place depressing storyline and the slow movement speed. That's literally my own complaint though. A depressing plot about revenge, betrayal and guilt in a game that rewards you quite highly for shooting someone in the balls and then kicking them in the face is just...weird. Like Michael Bay's Transformers, tonal inconsistency. But that doesn't mean Bulletstorm isn't a goddamn fun shooter you can really enjoy if you like wacky, creative weapons and mowing down tons of dudes in stylish ways. And if you don't, what the hell is wrong with you?
That last part was a joke, by the way.