Beat all the levels in "Knee-Deep in the Dead"
Beat all the levels in "The Shores of Hell"
Beat all the levels in "Inferno"
Beat all the levels in "Thy Flesh Consumed"
Beat DOOM in under 2 hours
Get 25 kills in deathmatch
Get 100 kills in deathmatch
Beat every level on Nightmare in co-operative mode
Get 25 kills with your fists in a single level
Get 3 multi-kills with the shotgun
Finish off a Cyberdemon with the pistol
Kill 5 enemies in 5 seconds with the plasma rifle
Kill only a single enemy with a shot from the BFG
Kill 2 enemies with a single barrel explosion
Crush a corpse in a door
Finish a level with 200% armor and 200% health
Find a secret level
Find all the secret levels
Kill one of every enemy