The game was originally slated for a December release, which would have put it in Nintendo's Wii U launch window. Unfortunately, the developer issued a last-minute delay in order to give the game one last spit-shine before it's release. It will be available for download via the Wii U eShop on April 4th, for real this time.
Two Tribes also has PC and Mac versions of "Toki Tori 2" headed to Steam later this year. Sadly, no specific release date for those platforms has been confirmed just yet.