Here is the full list of all 43 Over 9000 Zombies! achievements.
Construct 1000 Turrets from random scraps of metal!
Kill 900,000+ Zombies!
Kill 90,000+ Zombies!
Construct 100 automated turrets.
Collect 100 Power Ups!
Voted the greatest zombie of all time!
No 8th symphony for zombie Sibelius!
Participate in a multiplayer game.
Kill over 1000 crabs!
Get 30 kills per second!
Vote for Zombie Thomas Jefferson, or don't.
The army of the undead will march at daybreak!
Kill over 1000 zombie eyes!
The zombie world is independent of our will.
Get 15,000 damage per second!
Abused patience turns to fury!
Health is the greatest gift, a close second is BRAINS!
Kill 9,000+ Zombies!
Terror possessed me then!
If only he had the body of a horse...
A jail is an isolated system.
Kill over 1000 zombie dogs!
Blood and Flesh can be trusted.
Decreased Zombotropy.
Derail the Waltz of the Undead!
Quoth the Raven "Nevermore."
Kill over 1000 zombie crows!
Don't call me slow!
Your world didn't end!
You didn't donate your organs...
It didn't taste like chocolate ice cream either...
Zombie Napoleon meets his zombie Waterloo!
Not a wimp.
Lots of progress!
Get 10 kills per second!
Kill 1000+ Zombies!
Get 5,000 damage per second!
You watched the world burn, and survived. It was kind of cool.
Green IS good.
Construct a turret from scrap metal!
You won that race.
Making some progress...
The first day is always the hardest, except in this case, it's the easiest.