I got the game yesterday and it's awesome so far. It's hard to believe they managed to do all the things in the story levels with the level creation tools.
Co-op is done extremely well again. We're only on world 3 so far and haven't laughed so hard playing a game since lbp 1. So far we've had the grapling hook, wich also hooks on eachother for interesting gameplay and hilarious screw ups. The power glove with which you can pick up and throw objects, and also pick up eachother and throw your partner up or off a ledge. You can even stack a tower 4 high of sack boys. Then there's the cakinator, basically platforms you can shoot anywhere that stick to all kinds of surfaces. (including sack boys)
The level I created was still there and it works in LBP2. The lighting looks a lot better in LBP2 although it does look a bit bland now compared to the new story levels. They dialed up the detail to 10 for this version.
Anyway get this game, it's amazing.
PSN id SvennoJ if you're looking for some co-op fun.