The Plasma Discharge Unit, also known as the grenade launcher, is the most powerful weapon in Blake Stone: Aliens of Gold. When fired, it launches fireballs which explode on impact. It uses up ammunition more quickly than any other weapon. The projectiles it fires do not affect the turrets.
This weapon drains 4% of the ammunition in Aliens of Gold and 8% in Planet Strike.
The explosions it creates when the grenades detonate cause splash damage. If the grenades hit a wall near an actor or player, the actor or player will still take full damage from this weapon.
The weapon this most closely resembles from Wolfenstine 3-D and its various mods/ports is the Flamethrower. Both in its behavior, in which it lobs a projectile that causes heavy damage and splash damage upon impact, and its relative scarcity.