Rayman Legends is postpone for a September release and will be releasing on multiple platforms.

Fortunately, The developers are aware of the outcry from Wii U owners and apologize to us with a free eShop download in April. It's not a new demo, they're competitive challenges with updated online leaderboards and supports up to 5 player locally. Some challenges are exclusive to the Wii U version.

Also you should note that the "finished" Wii U version will contain new features instead of waiting in a factor until September.