Kirby's Adventure Cheats
Successfully complete the regular game to view the ending credits. Then, defeat all of the Bosses in the "Vs. Boss" option at the "Bonus Games" screen. It will be the same ending, except Kirby will keep making mistakes.
Use HI-Jump and aim your jump at a monster. It will be killed when you hit it, and you will not be hurt.
Go to a Warp Star Station in any level with the Fireball power. Use the Fireball power to dash onto a star. Kirby will become yellow until he crashes to the ground on a star.
Press A + B + Select + Start during game play.
Defeat the Boss, then use the last Mike to hit the bonus plunger or piece of the star rod.
In world 1 level 2, grab any power and find the Warp Star. Walk away from it so it is just out of sight, then release your power with Select. The warp star will be gone and you can walk to the end of the level, where "HAL" will appear.
Successfully complete the game and save the game. An option to play the bonus games will appear when selecting that saved game from the title screen.
Successfully complete the game with a 100% rating.
Successfully complete the "Extra Game".