Here is the full list of all 12 All Zombies Must Die! achievements.
Complete a base quest without taking any damage
Complete "Return to the Military Base"
Complete "Dev Card Hunt"
Complete ALL character quests
Kill a Mutant with your fists
Fully upgrade a weapon with any status effect
Witness Luxo joining the group
Kill 500 Zombies in one level
Use your first Smart Bomb
Witness Brian joining the group
Witness Rachel joining the group
Kill a Zombie