Half-Life: Opposing Force

Opposing Force returns to the same setting as Half-Life, but instead portrays the events from the perspective of a U.S. Marine, one of the enemy characters in the original game. The player character, Adrian Shephard, is sent in to neutralize the Black Mesa Research Facility after a scientific mishap causes it to be invaded by aliens, but quickly finds that the Marines are outnumbered and slowly being beaten back by a second alien race and black operations units.

Developer

Gearbox Software

Publisher

Sierra Entertainment, Valve

Genres

Shooter, Platform, Puzzle

Released

November 10, 1999

Also known as

HL: OPFOR, HL: OP4, OP4