The Munchables is Katamari with platformer overtones which become more pronounced as the game progresses. Rather than rolling up misc objects the focus is on traversing stages like a typical 3D platformer and gorging on space pirates, who happen to be living fruit and vegetables. It's cute as a button, contains some replay and an acceptable catalogue of tunes to listen to.
The downsides are that it is only a clutch of hours in terms of a full play-through, despite being replayable in short bursts it isn't as replayable as Katamari games, and jumping requires the player to flick the remote rather than press a button (just plain silly, if the flailing control gimmick isn't needed then for God's sake spare us all and map commands to buttons).
Because of the above I'd say it's not a game to buy if you have a small collection, just because there needs to be a cool-down period before picking it up again. The kids should love it, however, as well as Katamari fans and anyone who likes this style of Japanese game.
Reviewers call it repetitive, but virtually any game could be called that, I think the main thing which holds it back, as well as the numerous other short-but-good games, is price. Play's offering this recent release for £10 (at the time of writing), it's a no-brainer. Save me a seat at the all-you-can-eat space pirate buffet.