The game: A very putziges & snug platformer that is not really supported by the story, but rather by collecting fragments and other useful items. The graphics are also quite respectable. Ausenareale are beautifully done and the lighting system is here very well to wear.
In co-op itself Knack flexes rather somewhat modest. As you can beat yourself, it can sometimes happen that you look at some places the game of life but a little heavier than desired design. Then makes it for the odd moment of frustration. But apart from power in co-op fun.
My conclusion: For platforming fans a must buy. For the undecided in the price can not be too much wrong one.