The titular little MOBA game on 360 and PC is making its way onto the xbox one, featuring CROSS PLATFORM PLAY with 360 users, 4 player splitscreen, and stull completely free to play.
http://www.ign.com/articles/2014/06/09/e3-2014-happy-wars-announced-for-xbox-oneFeaturing cross-platform play with the 360 edition and four-player split-screen, Happy Wars is slated to come out on Xbox One. Microsoft boasted that the free-to-play multiplayer online game has been downloaded 7.5 million times while making the announcement.
In addition, developer Toylogic is planning to include new characters and gameplay for Happy Wars on Xbox One, which doesn't have a release date yet. For more on the free-to-play title, be sure to check out IGN's review of the 360 version.