In ARMA 2: Operation Arrowhead, the player can assume the role of various military duties from simple infantry man to tank commander or pilot of a combat helicopter. Also in some scenarios the users are allowed to command units like a real-time strategy game. Players are allowed to perform duties that real soldiers would perform during combat. In addition to campaigns, players are allowed to play mini-missions and participate in a simulated training program.
ARMA 2: Operation Arrowhead features United States Army military equipment, albeit with some creative liberties taken by the developers. The U.S. Army's standard M16 rifle has been replaced by the SCAR-L and SCAR-H in-game. New armored vehicles that were not included in ARMA 2 include the U.S. Army's Stryker ICV and Bradley IFV. The U.S. Marine Corps that featured prominently in ARMA 2 are not included in ARMA 2: Operation Arrowhead, instead being replaced with U.S. Army soldiers, wearing the Army Combat Uniform in the Universal Camouflage Pattern. In addition, three new factions are included: NATO, United Nations peacekeeping forces from the fictional country of Chernarus, and the Takistani Army. NATO forces include the United States Army, the Army of the Czech Republic, and the German Kommando Spezialkräfte. One touted addition to the game includes the ability to have FLIR thermal imaging technology included on vehicles such as the AH-64D Apache Longbow, and featured as rifle optics. In the game, running vehicles and live humans will glow when viewed through FLIR imaging, as in real life.