Here is the full list of all 22 Death or Treat achievements.
Kill 1.000 enemies
Restore Pumpkin Store
Restore HallowTown
Unblock one improvement at Necrosoft
Conquer Darkchat for first time
Unblock one improvement at DetoxBucks
Restore Necrosoft
Restore Frank's armory
Restore Detoxbucks
Restore Joe's shop
Conquer Riptok for first time
Conquer Deviltube for first time
Conquer Faceboo! for first time
Unblock all weapons
Get all ingredients
Stock 10.000 candies
Stock 20.000 candies
Kill 6.666 enemies
Unblock all improvements at DetoxBucks
Unblock all improvements at Necrosoft
Restore all portals
Get all achievements