Punishment is a modification for Quake made by Robert DeFilippo III. This features a few alternate modes for Weapons that can be toggled on and off by using impulse keys.
The Super Nailgun can randomly fire a Tracer, a projectile that is lit up for a few seconds before disappearing.
Impulse 12 toggles the Split Missile feature. This mode for the Rocket Launcher fires (for the cost of 5 Rockets) a rocket that if given enough distance will split into 5 weaker rockets.
Impulse 13 toggles the Auto Shotgun feature. This mode for the Super Nailgun sounds like a Shotgun and fires 2 Shells, but otherwise functions the same as a Super Nailgun, allowing for rapid fire.
Impulse 14 toggles the Nail Grenade feature. This mode for the Grenade Launcher costs 3 Rockets and does not make a sound when fired. Bouncing off opponents, the grenade shall land before breaking apart and releasing an explosion into the air above it. Nails shall fall out of the explosion, showering whatever is below it.
Impulse 15 toggles the Nail Shotgun feature. This mode for the Shotgun fires 4 Nails at a time, but produces a ring of 6 Nails to emulate a Shotgun blast.