Obtain a sample of the metal used in Dark Trooper production

Destroy a Mouse Droid

Enter the Sewer

Pickup the Infrared Goggles

Return to your ship on the roof of the base

Complete Quake Episode 1: Dimension of the Doomed in single player.

Kill a monster with another monster's attack.

Cause an enemy to kill another enemy.

Defeat your opponent with their own Finisher. (PLAY mode against A.I.)

Use Payback Spray Poison Mist to your opponent's face. (PLAY mode against A.I.)

Locate the secret level 'Hectic'

Acquire all 3 Demon Key Artifacts in the main campaign

Defeat the Mother of All Demons on The Absolution