I've played a few hours into this, up to the vacation like beach, with my roommate. The additional player is only marginally fun, and difficult to get a hang of. The camera isn't great. The timed fighting areas is a little lame, only because if you fail, you have to wait around a few minutes, only to try again, just short of failing.
A lack of a decent map is annoying, we've been caught with no idea where we should go. Where we are currently, the storyline really doesn't make great sense, and I think most cutscenes and places where the gameplay ventures from the standard "pick things up, throw them down" have been to establish character and setting, because the story has been nothing special.
Fighting new enemies, and the rare boss here or there can be a lot of fun, though. Trying to make certain enemies react to certain things is what sells it. The problem is, timers give you so little time to exploit these things, or even to toy around with them, it's just painful.
We'll play more later, but the game has moved to our backlog, honestly. Who know what the order of that is, or when we'll have time to get to it.