Additionally, an unofficial sequel was previously being developed by fans named Opposing Force 2, however it has since been put on indefinite hold. A fan mod is currently in the works that will see the whole game remade in the Source engine currently titled Operation: Black Mesa. Shephard is sent into the Black Mesa Research Facility on an undisclosed mission, but things go wrong as he finds himself fighting for survival against government agents, Xen aliens, and the mysterious Race X. The expansion's single-player mode features the same setting as the original, with the twist that the player is cast not as Gordon Freeman, but as Corporal Adrian Shephard, a U.S.
Half-Life: Opposing Force is a critically acclaimed expansion pack for Half-Life, developed by Gearbox Software and released by Valve Software on November 1, 1999.
