Super Mario Bros. Dimensions

Super Mario Bros. Dimensions is a fan game by LangtonLion64. It features a dimension switching mechanic that changes the level and its challenges.

Taking place days after the events of Super Mario Bros. 3, Bowser is lost around the outskirts of the Mushroom Kingdom, where he finds a mysterious flashing ring. The ring can allow one to travel to an alternate dimension, one that is much less developed and a lot gloomier than the Mushroom Kingdom.