New Super Luigi U will launch as DLC on June 20 for $19.99. On August 25, it will hit stores for $29.99. Nintendo said this was to facilitate players who may not own the original game but want to play as Luigi.
Nintendo also announced that, since Mario is no where to be found in this version of the game, they've added a new fourth character for multiplayer: the thieving bunny Nabbit. This character can't power-up using items like Luigi and the Toads, but he doesn't take damage when he touches enemies. Nintendo suggests he should be used by players who find 2D platforming challenging, and he's only available in multiplayer.