New Super Mario Bros. Mii was one of the most "game-like" Wii U experiences shown at E3, mostly because it was essentially a higher-res version of New Super Mario Bros. Wii. The demo levels were newly created, and covered land, air, water, underground, and ice. As the title suggests, Miis could join Mario, Luigi, and Yellow and Blue Toad on their adventure, but all characters controlled the same.

The purpose of the demo was to show how the game could be played either on the Wii U controller or a TV screen. The game was streamed seamlessly to the New Controller screen, though otherwise, it didn't do anything differently from the Wii version. Four players could join in with Wii Remotes, but not when the New Controller was being used.

The higher resolution allowed for more play area, but the graphics were essentially the same as those found in New Super Mario Bros. The final level featured moving platforms that got pretty crazy near the end when three Lakitus flew in to toss Spinys. In this case, the camera zoomed out to let the view incorporate the enemies as well as the players.

It's not clear whether New Super Mario Bros. Mii will be turned into a full game, but I'd guess it's pretty likely.