This expansion pack to 2009's ARMA 2 features a standalone plot and setting and does not require installing the original game. Operation Arrowhead is set in an alternative 2012 in Takistan, a made-up mountainous Asian country reminiscent of Afghanistan. The protagonists are the NATO forces consisting of American, Czech and German military. Their mission is to overthrow the corrupt regime of colonel Muhammad Aziz and to protect neighboring (equally fictional) Karzeghistan from a Tatkistani invasion. The player will lead them through a series of battles in the desert, highland, and urban environment. At the various stages of the game, the player will control not only foot soldiers but also tanks and helicopters.

Operation Arrowhead adds certain new features to ARMA 2 gameplay. The expansion introduces additional vehicles and weapons, enhanced infrared vision, removable backpacks, and drones that can also be controlled by the player. There are also DLCs that allow you to add British soldiers and a private military company. The game is considered quite hardcore by its difficulty, even for experienced gamers, so it is recommended to complete a tutorial stage at the beginning.