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