Survive the first wave
Survive until the Fifth Wave
Survive until the Twentieth Wave
Survive the first two waves without firing a gun
Kill 5 zombies during a game before they crawl completely out of the earth
Collect as many points until you have 10,000 in a row
Explore the map by opening all the doors
Kill 10 zombies simultaneously with just one grenade
Avoid all damage taken in the first 10 Waves
Stay the first 5 waves in the starting building