Runbow is now available on Xbox One. Currently free for Xbox Live Gold subscribers until August 15th. The game is a platformer but features a variety of different modes to play and impressively supports up to eight players at once on the same screen in local multiplayer and nine when playing online.
The official game description:
Get Ready to Runbow! Runbow is a fast-paced action party game for up to 8 players locally and 9 players online. Platforms and obstacles appear and disappear with each swipe of the background color, so if you can’t see something, IT DOESN’T EXIST! Players can go head-to-head in Run, Arena, and King of The Hill, or hone their skills on their own in Adventure or The Bowhemoth.