Half-Life: Opposing Force (1999)

Half-Life: Opposing Force is an expansion pack for Half-Life developed by Gearbox Software and Valve Corporation. It was released in North America on November 19, 1999.

Special thanks to:

 * Harry S. Robins
 * Mike Shapiro - G-Man, Additional Voices
 * Jon St. John - Drill Instructor Dwight T. Barnes, Drill Instructor Sharpe, HECU Soldiers, MPs