- "While it has high damage potential, the concentrated beam of the Gauss Cannon demands accuracy from the user."
- ― Arsenal description [src]
The Gauss Cannon is a powerful and incredibly accurate weapon that fires steel flechettes (metal spikes essentially) at extremely high velocities using a magnetized chamber. Most enemies can be killed with one shot, though larger enemies, such as the Cacodemon and Baron of Hell, require more shots to kill.
The Gauss Cannon shares its ammo pool with the Plasma Rifle. The player can increase his max ammo cap by using Argent Cells and allocating its power to "Ammo" subsystem.
|"Ammo" Level||Max Ammo|
| Precision Bolt|
Use the Weapon Mod button to zoom in and charge a high damage shot.
|Energy Efficient||Reduced time to max charge and reduced time between shots.||3 / 6 Weapon Upgrade Points|
|Light Weight||Move at full speed when zoomed in.|
|Volatile Discharge||Demons killed by the Precision Bolt will explode, dealing damage to nearby demons.||Purchase all upgrades and complete the Weapon Mastery challenge|
| Siege Mode|
Use the Weapon Mod button to charge up a powerful beam that penetrates targets. Movement is disabled while using Siege Mode.
|Outer Beam||The beam now has a devastating area of effect around it.||3 / 6 Weapon Upgrade Points|
|Reduced Charge Time||Beam charge time is reduced.|
|Mobile Siege||Allows movement while using Siege Mode.||Purchase all upgrades and complete the Weapon Mastery challenge|
The Gauss Cannon is one of the 3 Power Weapons in Multiplayer. In this mode, it has 4 shots and ammo cannot be replenished. As with the BFG 9000 and the Chainsaw, the Weapon Mod allows the user to see enemies through walls. The weapon does 150 damage.
- Despite the name erroneously designating it as a coilgun, the Gauss Cannon is actually a portable railgun, with mechanics similar to the railguns of the Quake series.
- On the side of the weapon, it reads "Try Not To Die When Firing This Beast."
- The Gauss Cannon's recoil can be used to the player's advantage, launching you in the air as far as a double jump, and launching you even farther if you're moving backward.
- This method is similar to the rocket-jump technique from the Quake series.