HECU RPG

The Rocket Launcher, commonly referred to by the generic name RPG, is a shoulder-mounted, laser-guided rocket launcher used by the HECU in Half-Life.

It is acquired midway through the level "Surface Tension" in an alcove in a canyon wall. The player is given a chance to use the weapon after picking it up, as an HECU AH-64A Apache helicopter appears soon after.

Trivia

 * You can use the launcher's laser-guide to guide rockets launched by others as well. One application in the single-player game is to guide rockets launched by HECU vehicles away from you into walls, or even back at them.