Halo: Spartan Assault Steam Trailer

Set between the events of Halo 3 and Halo 4, this twin-stick shooter puts you in command of a Spartan that isn't Master Chief. It sees you shooting and stealing vehicles to shoot with - just like the FPS titles in the series.

It has been out for Windows 8, Windows Phone, Xbox One and recently Xbox 360, now it's finally coming to Steam on 4th April. It now features Steam achievements and leaderboards.