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