From Wikipedia: "Operation Flashpoint: Cold War Crisis (OFP) is a critically acclaimed tactical shooter and battlefield simulator released in 2001. Set on a group of fictitious islands in the year 1985, Operation Flashpoint (OFP) puts the player on one of three sides in a hypothetical conflict between the NATO and Soviet forces led by a renegade general. The Resistance, which generally sides with NATO, is the third playable faction. 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 the graphic and sound effects. The main feature of the game, distinguishing it from other shooters, is its close attention to realism."