Here is the full list of all 21 Envy the Dead achievements.
Use conviction answer
Complete stage 1
Defeat survivors in battle
Feed dying hungry character
Equip character with any armor
Kill stinker boss
Heal dying injured character
Defeat zombies in battle
Gather any supply on x8 rate
Explode barrel or propane
Train character to level 4
Craft turret
Kill butcher boss
Complete stage 2
Complete game
Complete stage 1 on hardcore
Complete stage 2 on hardcore
Complete game on hardcore
Survive wave 10 in survival
Survive wave 20 in survival
Survive wave 30 in survival