I usually buy these games for my Kids and I end up playing them. It's a great game I can play the main story and if they want to join they just turn on the controller and there's a little mini Knack and they can play along with me and when they get tired they can stop and the other Knack disappears and they can just watch. Or if they are stuck I can just jump in and help.
I'm usually pretty lax on even some of the more awful games, finding fun where there is little, but Knack is truly awful. Everything about it rubbed me the wrong way, and I hated everything about it. This is one of the worst games I've played in years.