Collect all the Gas Tanks
Defeat Tutorial Zombies without taking damage
Complete the Game on Easy Difficulty
Complete the Game on Medium Difficulty
Complete the Game on Hard Difficulty
Complete the Cave
Complete the Crypt
Complete the Hospital
Collect all the Keys
Save the Mountain Man
Save the Sheriff
Save the Farmer
Save the Drunk
Save the Housewife
Save the Jock
Save the Nurse
Save the Kids
Save the Gravedigger
Save the Shopkeeper
Finish the game with 100% Completion
Save all Survivors
