Complete any non-tutorial level
Died 100 times and still here
Kill 5 or more zombies in one shot
Complete level without taking any damage
Complete level without killing a single zombie
Kill 20 zombies in a row using only melee attacks
Kill 50 zombies in a row using only firearms
Kill 30 zombies in a row using only blunt weapons
Acquire all the available weapons
Retrieve five crossbow bolts from dead zombies
Upgrade all player abilities to maximum levels
Complete every level available in the game
Complete game on easy difficulty
Complete game on normal difficulty
Complete game on hard difficulty
