Here is the full list of all 43 Over 9000 Zombies! achievements.
Lots of progress!
Kill 1000+ Zombies!
Construct a turret from scrap metal!
You watched the world burn, and survived. It was kind of cool.
Green IS good.
You won that race.
Get 5,000 damage per second!
Voted the greatest zombie of all time!
Making some progress...
The first day is always the hardest, except in this case, it's the easiest.
Get 10 kills per second!
Kill 9,000+ Zombies!
Kill 90,000+ Zombies!
Kill 900,000+ Zombies!
Vote for Zombie Thomas Jefferson, or don't.
Not a wimp.
It didn't taste like chocolate ice cream either...
You didn't donate your organs...
Your world didn't end!
Don't call me slow!
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!
Zombie Napoleon meets his zombie Waterloo!