Pretty good.
Play mode is quite easy regardless of difficulty, even beating Hard without losing a life is quite easy.
Challenge mode, however, offers more variety of challenges.
Fun mode is like a challenge mode but easier.
One downside of this game is, it is not good at keeping track of how you're doing. There are trophies for completing all challenges and stuff, but beaten challenge and unbeaten challenge look the same. Same goes for Fun mode. And the menu is pretty slow and pretty much is a sub-GBA interface.
But for just 8MB, totally worth a spot in your memory card.