| Console: | PC |
| TV Standard: | Region Not Set |
| Developer(s): | Gearbox Software, Valve Corporation |
| Publisher(s): | Sierra |
| Release Date: | 1999-11-01 |
| Players: | 1 |
| Co-op: | No |
| ESRB: | M - Mature 17+ |
| Type: | Shooter |
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.
