Here is the full list of all 45 Of Orcs And Men achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Finish Of Orcs and Men at Easy level
Finish Chapter 5 at any difficulty level
Finish Chapter 4 at any difficulty level
Kill Emperor Damocles
Poison three different enemies at the same time
Learn every Skill in a single tree.
Equip a full set of upgraded equipment (weapons and armor)
Finish Chapter 3 at any difficulty level
Follow the path of the Berserker
Follow the path of the Master
Bind Skills to both of each character's shortcut keys
Follow the path of the Assassin
Follow the way of the Shadowgoblin
Kill the Imperial officer in the Monastery
Finish Chapter 2 at any difficulty level
Break 15 spinal columns while Berserk
Put together a special squad to assault the Pillar
Let Styx take out the Imperial sentinels of the Mire on his own
Assassinate 47 enemies
Prevent a miners' revolt in the Mire
Survive the Row
Complete Chapter 1 on any difficulty setting
Put an end to the madness of the Shaman of the Bowels
Hit eight enemies with a single attack
Deal with the Scourge issue in the shantytown
Kill Dorek the Trainer
Trade an item
Defeat a boss without using an automatic attack (assassinations excluded)
Upgrade a Skill
Have Styx calm things down a bit
Answer Sork's provocation in a language he understands
Save a brunette in distress
Win the Black Hand challenge
Kill Gorkash the Head Foreman without further ado
Kill all the dug-in foremen and guards
Spare Dakath the repentant
Take pure water to the Shaman of the Mire
Be buddy-buddy with a force of nature
Confront Braggart with his lies
Finish Of Orcs and Men at Normal level
Finish Of Orcs and Men at Hard level
Finish Of Orcs and Men at the highest difficulty level
Learn and improve every Skill in a single tree.
Find and empty 20 chests
Put together the best squad possible to assault the Pillar