Super Mario World/cheats

Fall theme and different enemies
One of the hardest challenges in any Mario game is to find all of the 96 level exits in Super Mario World. If you do, however manage to find them all, the world map will change from summer to fall. Many of the enemies will also change - The Koopas will have Mario hats on them, the Bullet Bills will be bats, and much more.

Re-enter castles
Unlike the GBA remake, where you could re-enter any castle at any time, the original wouldn't let you, unless you typed in a cheat. To re-enter a castle, go to the selected castle, and press L and R buttons.