Here is the full list of all 43 Over 9000 Zombies! achievements.
The zombie world is independent of our will.
Kill over 1000 crabs!
Kill over 1000 zombie eyes!
Kill over 1000 zombie dogs!
Voted the greatest zombie of all time!
Kill over 1000 zombie crows!
Collect 100 Power Ups!
No 8th symphony for zombie Sibelius!
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.
Get 30 kills per second!
Blood and Flesh can be trusted.
Decreased Zombotropy.
Get 15,000 damage per second!
Quoth the Raven "Nevermore."
Kill 9,000+ Zombies!
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...
Not a wimp.
Lots of progress!
You watched the world burn, and survived. It was kind of cool.
Green IS good.
Kill 1000+ Zombies!
You won that race.
Get 5,000 damage per second!
Making some progress...
Construct a turret from scrap metal!
The first day is always the hardest, except in this case, it's the easiest.
Get 10 kills per second!
Participate in a multiplayer game.
Kill 90,000+ Zombies!
Kill 900,000+ Zombies!
Vote for Zombie Thomas Jefferson, or don't.
Construct 100 automated turrets.
Construct 1000 Turrets from random scraps of metal!
Derail the Waltz of the Undead!
The army of the undead will march at daybreak!
Zombie Napoleon meets his zombie Waterloo!