The plot of the game involves you, the player, as the head of a mercenary organization hired to lead a rebellion against an evil dictator. During the game, you need to gain the support of the population, many of whom run about the battlefield hoping to not be shot by either the insurgents or the government forces. As the insurgent, you need to undertake an "oil spot" campaign, gradually seizing terrain as you help the people of the fictional nation fight their dictator. Clearing, holding, and building upon your successes in the cities and villages, you must train militia fighters in the areas you seize in order to gradually control the entire country.
I just re-downloaded the game from Steam, and I've spent the past few hours amazed at how much population-centric COIN theory I found in this pre-9/11 video game.
Focus: Are there any other games which incorporate COIN theory?