Nintendo didn’t leave Luigi out of Super Mario 3D Land. He’s a playable character. Just like the Super Mario Galaxy series, Luigi jumps higher than Mario. Kenta Motokura, art director, explained in an Iwata Asks interview you will be able to use the other Mario brother during special stages. Special stages are bonus levels players can access when playing through Super Mario 3D Land after beating world 8-4.
The tanooki suit from Super Mario Bros. 3 makes a return in the Nintendo 3DS game. While you won’t be able to fly using it, you can turn into a statue. Enemies will ignore Mario when he is a stone statue. Koichi Hayashida, director, really wanted to have the stone transformation in the game. He went as far as chanting "Kshitigarbha" (the name of the statue) over and over. The suit’s transformation power made it into the game, but it was a challenge for Sugawara, the game’s programmer. Mario can also hide in question mark blocks called hatena boxes a la Solid Snake. He gets coins from the box while walking around in it.
Super Mario 3D Land also has a time attack mode. As a reward for beating a stage, you can face off in a race against a shadowy Mario. All stages support this feature and you can trade stage run times with other players through streetpass.