Microsoft is planning to launch Halo: Spartan Assault for the Xbox One on Christmas Eve. After launching on Windows 8 and Windows Phone 8 earlier this year, the Xbox One copy will debut for $14.99 as a digital download on the new console. An Xbox 360 version is also being developed, but that particular edition won’t be released until January. The Xbox One version is largely the same as the existing Windows 8 and Windows Phone 8 editions, but it does include a new online co-op mode with additional missions.