Super Mario Bros. 3

Hint: Warp from World 1 to World 8

On World 1-3, after the second boomerang punk, kill the Koopa on the white block. Then, stand on it and hold Down until you fall behind it.
Next, run behind the place where you can get an extra life. The mushroom character will say something, and you will have a whistle.
Go directly to the castle and get a Feather where the skelepunk is located. Fly up and right. Keep going right, then hit the box to get another whistle.
Use one whistle to get to a map. Then, use the other whistle to get to World 8.