According to the site, players will be able to play as members of the United States Army in a fictional region of west-Asia named Takistan[20], where the terrain is based on Afghanistan. Operation Arrowhead will include three new maps, a variety of new units, vehicles and equipment, as well as the eponymous campaign. Among the new units are a new array of US army personel and vehicles, Czech forces and German KSK units. UN peacekeepers are also present as an independent faction.

The expansion is a standalone, meaning it can be run without the content in the original ARMA 2, but players who purchased ARMA 2 will also be able to integrate that content into Operation Arrowhead. The developers plan on releasing some of the core changes introduced in Operation Arrowhead (such as performance optimizations) as patches, allowing regular ARMA 2 players to access to any engine improvements introduced in the expansion. New content, however, will remain exclusive to Operation Arrowhead.

Arma 2 OA can be purchased online via digital download at the Steam store here: http://store.steampowered.com/app/33930/

While you do not need ArmA 2 standalone to play Operation Arrowhead, if you do not own either game, Steam has a package for both games, allowing you to enjoy both great games. You can find that package, ArmA 2 Combined Operations here: http://store.steampowered.com/sub/4638/