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