Insomniac Games Halo Wars - Xbox 360

The story opens with UNSC forces retaking the planet Harvest from the Covenant. At your disposal -- should you choose to take command of UNSC forces -- will be everything from a corps of highly-trained Marines to the Warthogs, Scorpions, and Hornets you'll need for air and land attacks. You'll take stock of the map and decide between holding your ground or advancing on enemy strongholds, all while trying to navigate the local terrain and outsmart Covenant forces. And when you need something extra to tip the tide in your favor, UNSC leaders can provide you with the ability to mobilize highly specialized units or call the Spirit of Fire vessel for support from above. Covenant: A Capable, Playable Enemy Faction
That's right, Covenant is playable in this corner of the Halo universe. This alliance of alien species has manipulated advanced technology, firepower, and tactical prowess into a powerful force that is engaged in a Genocidal war against human race, having branded humans as heretics. With the ability to play as these tough, alien fighters, you'll have advanced shield technology, the modular Citadel at the heart of Covenant's colonizing power, and, of course, the iconic Scarab attack vehicle at your disposal, adding a whole new dimension to your strategic warfare. The Scarab is a terrifying military vehicle crafted from heavy mining equipment. And with a mining laser that delivers massive damage across battlefields large and small, turrets for taking on air attacks, and the ability to clamber over any terrain, what's not to love about commanding Scarabs instead of fighting against them?