Series creator Shigeru Miyamoto has shared more details on the 3DS Mario title that Nintendo teased at the most recent Game Developers Conference. Edge reports that the Miyamoto says the game is "a combination of Super Mario Galaxy and Super Mario N64." That doesn't mean recycled levels, though, as he also claimed the game is "completely original, and coming this year." Of course, "this year" might only refer a Japanese release.
As for the mysterious tail seen in the logo, Miyamoto isn't exactly playing coy with its meaning. "The tail you mentioned on the logo -- it's what you think it is," he said. "You probably know what's going to happen using that character." Fans have speculated that it was a reference to the Raccoon tail from Super Mario Bros. 3, and it sounds like Miyamoto is all but confirming it.
Miyamoto promises that the 3DS' capabilities will make judging distance and platforming easier. "For example, the floors floating in space: in 2D it's difficult to judge the distance, but in 3D it's really easy." He also revealed the game will be playable at E3, so we should be able to understand how the Galaxy/N64 combination works then.