Complete the indicated task to unlock the achievement.

Achievement	How to unlock
BOOM! Headshot	Buy the Sniper guard.
Cheap guns	Place 500 Handgun guards.
Cold Blooded	Freeze 200 zombies.
Don't Stop Firing!	Place 500 Rifle guards.
Door Master	Close 100 doors.
Endless Horde	See the Game Over screen for the first time.
Engineer under preassure	Repair 30 doors.
Fireworks	Kill 300 zombies using the explosive barrel.
I am rich!	Reach 3000 supplies in one game.
KABOOM!	Buy the Rocket Launcher guard.
Lucky	All Scientists must survive 10 waves in a row.
Meat Fest	Kill 100 zombies in one game.
Now Hiring	Place 999 Guards.
Pieces Everywhere!	Buy the Shotgun guard.
Red Paint	Kill 30 zombies in one game.
Rest in Pieces	Buy the Gatling gun guard.
Survivor	Kill 1000 zombies in one game.
That was close...	Survive 30 waves in a row.
The Beginning	Survive the first wave.