Nintendo’s own official Gamecube controllers don’t work with the Wii U without a special adapter, and when they do, the only game they can be used to play is Super Smash Bros. Fortunately, these restrictions don’t apply to the Wii U controllers PDP are releasing.
PDP’s “Wired Fight Pad” controllers are Wii U controllers that are designed to look and feel like Gamecube controllers. They have a similar shape and button layout, and come in Nintendo-styled themes like Link, Samus, Donkey Kong and Wario. A Wired Fight Pad controller plugs directly into the Wii Remote and will work with any Wii/Wii U game that supports the Classic Controller, the Classic Controller Pro.