Reach the end of 'The Plutonia Experiment'.

Reach the end of 'Master Levels for DOOM II'.

Reach the end of 'DOOM II'.

Get 100 Chainsaw kills.

Finish off a Cyberdemon with the Pistol.

Kill 4 enemies in 1 shot with the Super Shotgun.

Get 25 kills with your Fists in a single level.

Gib three or more enemies with a single rocket explosion.

Kill 5 enemies in 5 seconds with the Plasma Rifle.

Complete any monster-filled level with 100% kills without getting hurt on Ultra-Violence or higher.

Kill all monsters in any monster-filled level on 'Hurt me plenty' or higher.

Cause an enemy to kill another enemy.