Here is the full list of all 43 Over 9000 Zombies! achievements.
Derail the Waltz of the Undead!
The army of the undead will march at daybreak!
Kill over 1000 zombie eyes!
Kill 90,000+ Zombies!
Construct 100 automated turrets.
Kill over 1000 crabs!
Voted the greatest zombie of all time!
No 8th symphony for zombie Sibelius!
Kill over 1000 zombie crows!
Kill over 1000 zombie dogs!
Get 30 kills per second!
The zombie world is independent of our will.
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.
Get 15,000 damage per second!
Decreased Zombotropy.
Quoth the Raven "Nevermore."
Collect 100 Power Ups!
Don't call me slow!
Your world didn't end!
Kill 9,000+ Zombies!
Participate in a multiplayer game.
You didn't donate your organs...
It didn't taste like chocolate ice cream either...
Vote for Zombie Thomas Jefferson, or don't.
Not a wimp.
Lots of progress!
You watched the world burn, and survived. It was kind of cool.
Zombie Napoleon meets his zombie Waterloo!
Green IS good.
You won that race.
Kill 1000+ Zombies!
Get 5,000 damage per second!
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!
Kill 900,000+ Zombies!
Construct 1000 Turrets from random scraps of metal!