Return of Donkey Kong
From the Super Mario Wiki
Return of Donkey Kong is a cancelled game for the NES. It was a scrapped sequel to the Donkey Kong arcade games. No screenshots or videos have ever been released, but news in the Offical Nintendo Player's Guide in 1987 said Mario was a playable character. The guide also stated Donkey Kong himself was a playable character. There would also be more levels then the originals had.
It is commonly believed that this game influenced Donkey Kong for the Game Boy.

