A very very fun game, an old N64 favorite.
The only thing I don't like is how short it is. I've played it many times, so that's how I have racked up the hours, but the game from start to finish is only a few hours. I don't REALLY have a problem with it, but the game is definitely very easy.
Really, everything else is good. The music is fitfully cheery and the graphics make the game INCREDIBLY cute. The game plays out like a typical 2.5D game like Goemon's Great Adventure. The thing that makes this game truly unique from the other platformers, and indeed different than the other Kirby games is the ability to combine powers. Kirby has been able to copy enemies powers for almost the entire series, but in this game any power can be combined with any other power to make a new ability. A lot of them are very cool like the fire sword (Fire, Cutter), the fridge (Electric, Ice) which is commonly considered the best because it dispenses healing items, and the exploding ninja star (Bomb, Cutter). Those are just a few of them, a lot of the fun is discovering what all the combinations are. This game really is a joy to play.
In conclusion, this game is definitely deserving of at least a playthrough. It might not be your cup of tea, but it's one of my personal favorites.