Survive the first wave

Kill 30 zombies in one game

Kill 100 zombies in one game

Kill 1000 zombies in one game

Survive 30 waves in a row

Reach 3000 supplies in one game

All Scientists must survive 10 waves in a row

Buy the Shotgun guard

Buy the Sniper guard

Kill 300 zombies using the explosive barrel

Repair 30 doors

Close 100 doors

See the Game Over screen for the first time

Place 999 Guards

Freeze 200 zombies

Place 500 Handgun guards

Place 500 Rifle guards

Buy the Rocket Launcher guard

Buy the Gatling gun guard