Hoshi No Kirby 64
Also know as: Kirby 64: Crystal Shards
to all the information you'll need on this game, and more!
If you collect all the crystals in the game (100%), you will unlock two secret modes:
Boss Battle (Bosubuchi)
You will be able to fight all the bosses.
Movie Viewer (Zenbu Miseru)
Lets you view all the game's cut scenes