The Grenade Launcher is the Duke Nukem 64 alternative to the RPG from Duke Nukem 3D. The weapon fires projectiles similar to that of the Battlelord mortars. A single grenade deals enough damage to kill a Pig Cop, although an Octabrain may require more than one grenade. It has roughly the same fire rate as the RPG. The grenades bounce and roll for roughly three seconds before detonating, so they can be used strategically to kill enemies that aren't aware of Duke's presence. The Grenade Launcher's maximum ammo capacity is 48, close to that of the RPG. However, every ammo container is worth 12 grenades, so ammo is more abundant for the Grenade Launcher than it was for the RPG.
The Grenade Launcher's ammo containers use a blue sprite. For other weapons in the game, blue ammo sprites are typically reserved for weapons that use a secondary ammo type. The secondary ammo containers use red sprites, while the standard ammo containers use blue sprites. This is no coincidence; there was originally a secondary ammo type planned for the Grenade Launcher. The following text ("Gas Grenades!") is found inside the game's memory files:
EXPLOSIVE SHOTGUN SHELLS!
The Grenade Launcher resembles the Hawk MM-1 grenade launcher.