Revealed in concept art by former Retro Studios employee Sammy Hall, Retro Studios actually worked on two major projects for Nintendo using two of their biggest IPs before Nintendo cancelled them for unknown reasons.

One of them was a project in the Mario series centered around the supporting character Boo. Little is known about the project outside of the Concept art, but hints released with the concept art tease that it would have been released for one of Nintendo's handhelds (such as the DS) as well as there being things in the game referred to as "possession powers" and "Broomies".

The other game, rumored to be centered around the character of Sheik from The Legend of Zelda series, was more elaborate. Hints leaked by Hall and released with the concept art suggest that it would of been about, and centered around, the origin of the Master Sword in the Bad Timeline and would feature "the last Sheik" as it's main character. The game would have also seen the Dark Gerudo tribe engaging in their decade-long birth to Ganon. The project was describe as an "Action/RPG".