Here is the full list of all 16 CARNAGE OFFERING achievements.
Buy the tactical vest
Improve the grenade launcher to the maximum
Improve the rocket launcher to the maximum
Upgrade all weapons and equipment in the store
Kill 50 zombies
Kill 50 witches with the power enhanced grenade launcher
Repair the turret
Kill 66 demons with the upgraded double barrel shotgun
Destroy the replicator ship at level 5
Destroy 100 machines
Kill the final boss in normal mode
Kill the final boss in hard mode
Kill the final boss in impossible mode
Kill the worm in impossible mode
Assembling the Peacemaker
Assembling the Smart Armor