Halo: Spartan Assault expansion arriving August 29

Microsoft today announced Operation Hydra, the first expansion for $7 Windows 8 and Windows 8 Phone game Halo: Spartan Assault. The content will be released on August 29 for free.

The Operation Hydra expansion adds five new missions to Halo: Spartan Assault, as well as new achievements. Players will rejoin Spartan Sarah Palmer in the content, as they embark on a mission to the core of planet Draetheus V's moon to discover the source of an alien signal.

The expansion also adds support for wired Xbox 360 controllers, allowing players to control the Spartan-IV soldiers through the familiar input on Windows 8 PCs and tablets. On top of this, power weapons previously only available through in-app purchase can now be acquired through using XP.

In addition, Microsoft has released 512MB version of Halo: Spartan Assault in the Windows 8 Phone Store for all carriers. A free demo of the game will be available on August 30 featuring one mission and a gameplay tutorial.

Halo: Spartan Assault launched in July and is the fastest grossing Xbox Live title in the Windows Phone Store based on revenue for the first 30 days of availability, according to Microsoft. It was developed by Vanguard Games (Gatling Gears, Greed Corp) in association with 343 Industries.

The twin-stick-controlled top-down shooter takes place between the events of Halo 3 and Halo 4. The game contains 25 missions, integration with and Halo 4 that includes additional experience points and unlockable Spartan emblems, and in-app purchases. Check out GameSpot's latest coverage for more information.