Yoshi's Island:
Super Mario World 2

999 lives:
Enter world 4-1 find the two long pipes that are hanging upside down. Kill the Piranha Plants, then swallow Shy Guys until accumulating six eggs. Grab a Koopa Troopa, and stand on the pipe that previously held the lower Piranha Plant. Spit out the shell between the two lower pipes. As the shell bounces back and forth, throw away an egg. Shy Guys will appear from the other pipe and will be hit by the shell until extra lives appear.

Perfect score:
Six stars will appear on the title screen if a perfect score is obtained.

Level 3:
Enter SVHYO as a password.

Play the Mini Battle Bonus games:
Highlight any completed stage on the Map screen,
hold SL and press X, X, Y, B, A. Then choose a game.