• To unlock boss rush mode in the main menu get 100% in a game.
• Beat the final bosses to get metaknight’s sword which appears in front of the magic mirror.
• To unlock the sound test option find the CD treasure during game play.
• Collect every treasure in the game to unlock arena mode.

Collect the cans of spray paint throughout the game to change Kirby’s color.

After defeating a boss, before it disappears, you can suck them up to change your power to the boss's power. That way he might not have to go to waste!

If you're looking for the last few areas for 100%, go to each map and if the map is not blinking, you have missed something (a treasure) on that map.