In the December 1997 issue of The64Dream, Miyamoto stated that Super Mario 64 2 would have made Luigi a full part of the game, and that if he was really popular, then the box for Super Mario 64 2 would be green.

There is a cancelled sequel for Super Mario 64, commonly called "Super Mario 64 2" or "Super Mario 128" (not to be confused with the tech demo of the same name) for the failed N64 DD. Only one demo was ever made, but was never shown to the public. The only information known about the game is that Luigi was going to feature in it, and co-operative play was a speculated feature. Since these two elements feature in Super Mario 64 DS, it's possible that other elements from Super Mario 64 2 were incorporated into Super Mario 64 DS.