INSURGENCY: Modern Infantry Combat (also known as INS) is a total conversion mod for Valve Software's Source Engine. Insurgency is a multiplayer, tactical first person shooter. The game is primarily set in Iraq, however some maps are set in Afghanistan.
The game is primarily a team-based, multiplayer online shooter focused on tactical, objective-based gameplay. The player can join one of two teams, the US Marines, or their adversaries, the Insurgents. Teams are structured around two squads, for a total of 16 maximum players per team. Within this team structure are limited player classes, such as the Rifleman, Support Gunner, Engineer, or Marksman.
The game has a pseudo-realistic portrayal of the weaponry used. There is no on-screen crosshair and the players must use the iron sights of the game's weapon model to accurately aim the weapon. Shooting "from the hip" is still possible; however, the free-aim system makes this difficult. Weapons are also deadly, with most rifles capable of taking out players with one or two shots to the torso. According to their class, players can also use fragmentation grenades, smoke grenades, and RPGs.
Maps are generally focused on urban warfare, even though there are suburban and outdoor settings.
Source: Wikipedia, "Insurgency: Modern Infantry Combat", available under the CC-BY-SA License.