Development Range: 1988-1990, SNES
Prerelease media for Super Mario World has always been shrouded in an enigmatic mystery, where the only notable plausible source of information was the SNES Test Program. This changed with the July 2020 Nintendo leak of the game's data, which contained a huge chunk of developmental materials featuring lots of never-seen-before graphics that were almost never released to the public.
There are a ton of leftovers from when the game was growing out of its Super Mario Bros. 3 phase to around the game's release, such as sprites done in the former game's style before the redesigning process. There's also loads of early new concepts that range from mockups to alternate designs.