It is based on an improved Flashpoint engine and it was released under the title ArmA Combat Operations in the United States on May 4, 2007. In 2006, Bohemia Interactive released a sequel called ARMA: Armed Assault. Operation Flashpoint was praised for its attention to realistic combat. An Xbox port was released in 2005 under the title Operation Flashpoint: Elite. Two expansion packs were released Gold Upgrade, which included Red Hammer, a campaign from the Soviet perspective, and Resistance, which introduced various new features and improved graphics and sound effects. The Resistance is the third playable faction. Set on a group of fictitious islands in 1985, Operation Flashpoint puts the player on one of three sides in a hypothetical conflict between American and Soviet forces. It was released on Jin Europe and Augin North America. The game uses the same engine, Real Virtuality, as the military simulator VBS1. Operation Flashpoint: Cold War Crisis, sometimes shortened to Operation Flashpoint ( OFP), is a tactical shooter and battlefield simulator video game developed by Bohemia Interactive Studio and published by Codemasters.