Secret Room with Five Lives
In Stage 2 of World 7, Rainbow Resort, fly up to the ledge directly above the level's entrance. Stand on the ledge directly above the door, then fly straight up to a secret door that allows you to skip the stage's first three mini-bosses. You will only have to fight and defeat the stage's four other mini-bosses. After you've defeated the final boss, Flame Mane, you'll enter a secret room that contains five 1-ups. Exit this room through the door on your right.
Secret Moon Room
Stop just before entering the last door of Stage 6 on World 7. Fly up to the moon and place yourself under it. A secret door will lead you to full life and a 1-up.
HAL Easter Egg
In Stage 2 of the first world, reach the warp star, but don't touch it or go past it. Fly near the top of the screen and back away from it so it disappears off-screen, then fly near it again. Keep flying back and forth so the star keeps appearing and disappearing from view. The warp star will disappear. after you do this a few times. Proceed through the level. There should be no more enemies. At the end of the stage you'll reach an arrangement of destroyable blocks that read HAL. HAL Laboratory created the Kirby character and "Kirby's Adventure."
Mike Glitch
Kirby's microphone is a devastating sonic weapon that will destroy almost every opponent on screen at once. You can glitch the game so you can use the mike 266 times. Copy the mike ability from an enemy that has it, then save it until you reach one of the pink star buttons that unlocks a part of the stage. Jump up above the star button and fall down onto it. In the instant before you hit the button, use the mike ability. If you time it correctly, the ability number next to the star in the bottom right corner of your screen should read "00," but you will still be able to use the mike ability.
Unlockables
Beat the normal game with a 100 percent completion rating to unlock the extra game, which is the same as the normal game with added difficulties such as fewer lives and hit points and no save game ability. Beat the extra game with a 100 percent completion rating to unlock sound test.
In-Game Reset
Press "A," "B," "Select" and "Start" simultaneously to reset the game.