Here is the full list of all 68 Zombie Army Trilogy achievements. It takes around 30-35 hours to unlock all of the achievements on Windows.
Reach Wave 10 in Horde Mode – Dead Man's Bluff
Find and shoot every Bottle of Blood
Collect every Gold Bar
Kill 25 Fire Demons
Complete every Survivor sidequest
Reach at least Wave 10 in Horde Mode – Flood of Tears
Sever 10,000 limbs
Successfully complete all Chapters on Sniper Elite difficulty
Complete levels as every playable character
Reach at least Wave 10 in Horde Mode – Waves of Despair
Save the man in the hospital
Shoot the 3 Zombie Ravens outside the Folterschloss
Put the tortured souls in the Forest out of their misery
Kill 25 Summoners
Reach at least Wave 10 with the highest score in any Horde Mode map
Reach at least Wave 10 with more gold medals than your companions
Reach Wave 10 in Horde Mode – Dead End
Reach a total shot distance of 50km
Complete any Campaign chapter in 4-player co-op at any difficulty level
Kill 100 Zombie Snipers
Successfully complete Tower of Hellfire
Get a 5-for-1 kill with any sniper rifle
Score 5,000 with a single sniper round
Successfully complete Terminal
Successfully complete Crucible of Evil
Successfully complete Gateway to Hell
Successfully complete Purgatory
Kill 50 Super Elites
Kill 5,000 enemies of any kind
Successfully complete Subway to Hell
Successfully complete Army of Darkness
Kill 500 Skeletons
Successfully complete The Keep
Pick up a phone
Successfully complete Forest of Corpses
Revive other players 50 times
Reach at least Wave 10 in Horde Mode – Cathedral
Kill 50 enemies that are actively attacking other players
Kill 20 Elites in co-op
Headshot a Heavy Armour Zombie without removing his helmet
Loot a Chainsaw Elite's corpse
Get an unbroken 10-headshot streak
Successfully complete Freight Train of Fear
Kill 20 enemies as they revive
Successfully complete Library of Evil
Successfully complete Labyrinth of Death
Reach a Chain Count of 30
Successfully complete City of Ashes
Become possessed
Sever 1,000 limbs
Kill 50 Suicide Zombies
Successfully complete Cathedral of Resurrection
Kill an Occult General
Kill a Zombie Sniper in mid-air
Defeat 500 enemies with headshots
Loot a Super Elite's corpse
Successfully complete Village of the Dead
Pick up a Panzerfaust
Pick up the Preacher
Kill a Suicide Zombie by hitting his grenade
Kill a total of 20 enemies while incapacitated
Get at least 15 for 1 with an explosive kill
Get at least 20 for 1 with an explosive kill
Reach a Chain Count of 20
Get at least 10 for 1 with an explosive kill
Kick 50 enemies down
Kill a Survivor
Reach a Chain Count of 10