Kirby has had a lot of games, but I really enjoyed this game the most besides maybe Canvas Curse.
The three animals giving Kirby a bit power-up added the gameplay. The Hamster was worthless, but the fish was great underwater, and the Owl made you a killer in the skies.
Despite the Kirby games being mostly easy, collecting all the rainbow shards to form the rainbow sword is a tough challenge. And beat the final boss with the rainbow sword is one of the toughest fights in gaming history. It wouldn't be so bad if you they healed you after he transforms.