First Eagles: The Great War 1918 (Also called First Eagles: The Great Air War 1918) is a PC game (Combat / Flight Simulator) that focuses on World War I between 1917 and 1918.
First Eagles has had fair success in the PC games market, although its impact has a lot to do with the game having an 'open architecture' allowing others to modify and improve aspects of it and add new planes, terrain, weapons etc.
In 2007, First Eagles: Expansion Pack 1 was released that adds the Sopwith Camel, Albatros D.III, Albatros D.Va, and Fokker Dr.I. This pack also includes new campaigns set over the Cambrai sector of France.
In 2008, First Eagles: Gold, a combo pack that contains both the original First Eagles and Expansion Pack 1, was released.
In Feb 2010, "First Eagles 2" was released, following the trend of upgrading to be compatible with Vista and Windows 7.
The game is based on the "Strike Fighters" engine developed by Third Wire Productions.
Source: Wikipedia, "First Eagles: The Great War 1918", available under the CC-BY-SA License.