POWER is a modification for Quake. It has no documentation included with it.
This modification alters the Super Nailgun so that it causes explosions that are identical to those caused by a Rocket Launcher.
The Shotgun and Double-Barrelled Shotgun receive a similar particle effect, but do not have the Splash Damage of a Rocket Launcher or the modified Super Nailgun. A Shotgun causes 72 damage per shot, while a Double-Barrelled Shotgun causes 168 damage.