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