See the Game Over Screen for the First Time

Kill 50 Zombies

Kill 200 Zombies

Kill 1000 Zombies

Survive For 10 Minutes

Kill 50 Zombies With The Shotgun

Kill 50 Zombies With The Grenade Launcher

Kill 50 Zombies With The Rifle

Pick Up an Ammo Crate

Use a Rocket Launcher

Unlock The 'Entrance' Level

Unlock The 'Prison' Level

Unlock The 'Power Room' Level

Unlock The 'Offices' Level

Unlock The 'Hallway' Level

Kill 10 Vermins

Kill a Bleeder

Kill 10 Bleeders

Kill 30 Vermins

Kill 30 Bleeders

Unlock 1 file

Unlock the First 8 Files