This article lists all of the cheats in Super Mario World.
Fall theme and different enemies
One of the hardest considered challenges in any Mario game is to find all of the 96 level exits in Super Mario World. If Mario and Luigi do find them all, the world map changes from summer to fall. Many of the enemies also change such as the Koopa now have Mario's cap on them, and now look like Mini Mario's, Bullet Bills are all replaced with bats, etc.
There are two different level colors (yellow and red). Red indicates that there is a secret pathway in the level while the yellow indicates that it lacks one.