Microsoft has Halo: Spartan Strike (iTunes Link) for the iPhone, iPod Touch, iPad in the iTunes App Store for $2.99 (regularly $5.99) for a limited time.

Delve into 30 challenging missions through cities and jungles using a devastating arsenal of weapons, abilities and vehicles including the iconic Warthog against the Covenant and Promethean enemies.

You are a Spartan supersoldier in this classified ONI simulation that starts during the events of Halo 2 on New Mombasa in 2552. Lead UNSC troops through numerous missions battling against new enemies to save Earth from being overtaken.