Also from Kirby GCN, it shows the ability to stack multiple players/helpers before this game uses it.
One part of the development is a stage that is played in full 3D. Later on, this concept is revisited in Kirby: Planet Robobot's Kirby 3D Rumble.
Development Hell: This game started as the Nintendo GameCube title, was scrapped, then went through several re-imaginings until this became the final product. According to this interview, development started as soon as Kirby 64 was completed, meaning it took eleven years for it to be released.
The Other Darrin: Director Shinya Kumazaki and one of the design staff take over for Dedede and Meta Knight, respectively. (Bandana Waddle Dee is silent.) They do a good job imitating Sakurai, Dedede's previous voice actor, and Atsushi Kisaichi, Meta Knight's previous Japanese voice actor.
Recycled Script: This game is essentially the gameplay of Kirby 64: The Crystal Shards merged with the plot of Milky Way Wishes. There are 120 energy spheres scattered throughout the game that require skill, paying attention, and/or having the right power to collect them. Two of Kirby's enemies team up with him. As for the plot, Magolor asks you to collect the lost parts of his ship so that he can return home, then he offers to take you there. Once there, you retrieve a dangerously powerful artifact, which Magolor steals from you to rule the galaxy, and you have to stop him.