Spartan Strike is the follow-up to twin-stick shooter spin-off Halo: Spartan Assault, and is once again developed by Vanguard Games and produced by Microsoft's Halo custodian 343 Industries.
Spartan Strike is set during the events of Halo 2 on New Mombasa in 2552. There are 30 missions in which you lead UNSC troops through cities and jungles. There's gameplay in the video below.
Microsoft is selling a Halo: Spartan Bundle on Steam for £6.99. This includes both Spartan Assault and Spartan Strike. Spartan Strike on its own costs £4.79 on Steam.
The Steam version supports keyboard and mouse and USB Xbox controller. The mobile versions use virtual joysticks for touch.