Here is the full list of all 43 Over 9000 Zombies! achievements.
Kill over 1000 crabs!
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.
Kill 9,000+ Zombies!
Zombie Napoleon meets his zombie Waterloo!
Get 30 kills per second!
Decreased Zombotropy.
Kill over 1000 zombie dogs!
Quoth the Raven "Nevermore."
Kill over 1000 zombie crows!
Don't call me slow!
Get 15,000 damage per second!
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!
Construct a turret from scrap metal!
You won that race.
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!
Kill 90,000+ Zombies!
Kill 900,000+ Zombies!
Vote for Zombie Thomas Jefferson, or don't.
The zombie world is independent of our will.
Construct 100 automated turrets.
Construct 1000 Turrets from random scraps of metal!
Collect 100 Power Ups!
Participate in a multiplayer game.
Kill over 1000 zombie eyes!
No 8th symphony for zombie Sibelius!
Derail the Waltz of the Undead!
Voted the greatest zombie of all time!
The army of the undead will march at daybreak!