Approach the Boss of Opposing Force to hear backwards audio composed of the phrase "To win the game you must kill me Randy Pitchford" when played correctly. Randy Pitchford is the leader of the development team at Gearbox Software.

Load the game with the "hl.exe -dev -console -game gearbox" command line. Then while playing a game, press ~ to display the console and enter one of the following codes to activate the corresponding cheat function:

Boot Camp

Regular game