I like how this game, Mario Galaxy, and a few others allow other players a degree of interaction in what is otherwise a single-player game. I think anyone who's married or otherwise has a significant other or just friends who game know that lots of times gaming in person means one person playing and one or more people simply watching. This is a nice way to let them be a little more involved, especially since most of the commercials/videos I've seen for Zack & Wiki emphasize that it's the kind of game where people besides the player are encouraged to point out solutions and help out.