Find a super secret

Complete The Way of All Flesh on any difficulty

Complete Even Death May Die on any difficulty

Complete Farewell to Arms on any difficulty

Complete Dead Reckoning on any difficulty

Complete Cryptic Passage on any difficulty

Complete Post Mortem on any difficulty

Kill a Choking Hand

Kill 100 Cultists

Kill yourself 10 times in single-player

Complete Ghost Town (E3M1) on any difficulty without any Innocents getting killed

Find the secret level in The Way of All Flesh

Find the secret level in Even Death May Die

Find the secret level in Farewell to Arms

Find the secret level in Dead Reckoning

Find the secret level in Cryptic Passage

Find the secret level in Post Mortem

Exploit the Hellhound's greatest weakness

Complete The Haunting (E2M5) in under 40 seconds on any difficulty

Defeat the 3 Beasts of Beauty and the Beast (E6M8) in under 3 minutes on Well Done difficulty or above