Here is the full list of all 43 Over 9000 Zombies! achievements.
Kill over 1000 crabs!
Get 30 kills per second!
Collect 100 Power Ups!
The zombie world is independent of our will.
Kill over 1000 zombie eyes!
Abused patience turns to fury!
Get 15,000 damage per second!
Health is the greatest gift, a close second is BRAINS!
Terror possessed me then!
Kill over 1000 zombie dogs!
If only he had the body of a horse...
Vote for Zombie Thomas Jefferson, or don't.
Kill 9,000+ Zombies!
The army of the undead will march at daybreak!
A jail is an isolated system.
Blood and Flesh can be trusted.
Decreased Zombotropy.
Quoth the Raven "Nevermore."
Kill over 1000 zombie crows!
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!
Zombie Napoleon meets his zombie Waterloo!
Derail the Waltz of the Undead!
You watched the world burn, and survived. It was kind of cool.
Kill 1000+ Zombies!
Green IS good.
Construct a turret from scrap metal!
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!
Construct 100 automated turrets.
Construct 1000 Turrets from random scraps of metal!
Participate in a multiplayer game.
No 8th symphony for zombie Sibelius!
Voted the greatest zombie of all time!