This game is definitely fun, however it's way too short. I was able to get through the initial mode where you uncover all of the characters in less than an hour, getting past the boss stages the first time in many cases.
The fun of the game is the novelty of playing mini games on the touch screen, and even using your breath for some of them. However, I felt kind of lightheaded after a while and I'm sure the people on the airplane thought I was crazy blowing on the DS.
The game needed a lot more depth. This is definitely a rent game and you should be able to sail through it without spending the money.