Mother May I?
Defeat the Mother of All Demons on The Absolution
Walk the Path
Finish the Lost Levels mission
Secret Sleuth
Discover a secret area
My Cause is Just, My Will is Strong
Find the BFG9000
Unholy Firepower
Find the Unmaker
Persistence is the Key
Acquire all 3 Demon Key Artifacts in the main campaign
Rip and Tear!
Kill a Cyberdemon
That was Fun
Finish a 'Fun' Level
RVNH3CT1CD3M0???
Locate the secret level 'Hectic'
Escape Artist
Finish 'No Escape' on Watch Me Die skill level