Here is the full list of all 10 #KILLALLZOMBIES achievements.
Rack up to 30th level
Crash atleast 100 cars in one session
Earn 10.000.000 experience points in a session
Perform Rampage attack
Do not shoot for 6 minutes
Use melee attack 100 times in a session
Kill first undead boss
Stay live atleast 60 minutes
Kill 500.000 zombies
Kill atleast 1.000 zombies with each weapon type