Half-Life: Opposing Force

Standalone Expansion

Linux PC (Microsoft Windows) Mac

Gearbox Software · Published by Sierra Entertainment

Released November 10, 1999

Standalone Expansion of Half-Life

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.