Yoshi's Island: Super Mario Advance 3

Yoshi's Island: Super Mario Advance 3 is the portable port of Super Mario World 2: Yoshi's Island. Having a long full title apparently runs in the family.

Because it is for the most part a straight port, most if not all of the unused graphics from the original game remain.

World 0
While not unused, it's unlikely that any normal player not knowing about this would ever see it. The "World 0" icon can only be seen if you get a Game Over during the intro level, at which point your progress (or lack thereof) is saved. This icon is not present in the SNES version. In the SNES version, no equivalent exists: you are given an infinite number of lives on the intro level. Even setting your lives to zero via cheat code and then getting a Game Over will display only an empty file; the game does not save World 0 to SRAM.

SMA3 Title Screen
As with the previous game, the graphics designers at NOA must have been out to lunch or something while this game was being localized, leaving us with this uninspired logo outside of Japan.