Here is the full list of all 36 Sniper Elite: Nazi Zombie Army 2 achievements.
Kill 5000 enemies
Defeat 10 Fire Demons
Defeat the Final Boss
Defeat 20 Summoners
Defeat 100 ignited zombies
Become possessed
Loot an Elite's corpse
Kill 100 skeletons with explosives
Kill 2000 enemy grunts in co-op
Get a 5-for-1 kill with any sniper rifle
Defeat 500 enemies with headshots
Kill 20 Snipers in co-op
Kill 20 enemies as they revive
Successfully complete Chapter 5 with 4 players
Successfully complete All Chapters 4 players on Elite Difficulty
Kill any 100 enemy with the shotgun
Collect all Gold Bars
Kill 20 Elites in co-op
Kill 1000 enemies
Find and shoot all the bottles of blood
Get at least 15 for 1 explosive kill in 4 player co-op
Get at least 20 for 1 explosive kill in 4 player co-op
Kill the trapped Elite
Successfully complete Chapter 4 with 4 players
Kill 500 enemy grunts
Successfully complete Chapter 3 with 4 players
Kill a suicide grunt by hitting his grenade
Pick up a phone
Get at least 10 for 1 explosive kill in 4 player co-op
Successfully complete Chapter 2 with 4 players
Defeat a Fire Demon
Kick 50 enemies down in co-op
Successfully complete Chapter 1 with 4 players
Pick up a shotgun
Pick up the Preacher
Own 2 Nazi Zombie Army games