New Super Luigi U is upcoming downloadable content for New Super Mario Bros. U on Wii U, starring Mario's brother Luigi, Nintendo announced during today's Nintendo Direct.
The upcoming content excludes the more typical "Brothers" term from the title as Mario will not be making an appearance, it was explained. According to Nintendo, the game will be made available on the Wii U eShop; however, New Super Luigi U will follow a similar development timescale as full software, "so it will take some time."
This downloadable content will change the over-80 existing courses available in New Super Mario Bros. U into entirely new courses. While Nintendo remained tight-lipped about the game's features, New Super Luigi U is described as including "large-scale downloadable content."