Among the assets uncovered in the Gigaleak, a large-scale leak of internal server data from Nintendo in 2020, are assets for an early version of the titular island. These materials depict it as a top-down world map akin to the one in Super Mario World, with both a large version (for selecting individual levels) and a small version (for selecting worlds) that one could toggle between using a lens. Many of these assets, dated to the spring and summer of 1992, are repurposed from Super Mario World's own cut assets, sharing strong similarities to material which dates back to 1989, but including additional modifications to fit the new game.

Interestingly, other assets from around the same point in development already resemble the rotating island seen on the final game's title screen and during inter-world cutscenes. This was most likely conceived as an alternate approach to the zoomed-out map, indicated by a series of more unique top-down map tiles and graphics for world names that align with the assembled island. The world name graphics come in two variations: one with ten worlds, and another with just five (compared to the final game's six). The names of these worlds indicate a very different set of themes to what is seen in the finished game, including a "Ghost Town," a "Bottomless Swamp," a "Palace of Sea," and "Earth Bowels." Both versions of the early world map feature sprites for Yoshi traversing these areas a-la Super Mario World.