Here is the full list of all 38 Dark Souls II achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Learn all gestures
Discover a most brilliant covenant
Light all flames on the map in Majula
Max-out devotion to covenant
Discover the abysmal covenant
See the ending
Inherit Captain Drummond's equipment
Discover the covenant of the bloodthirsty
Discover the covenant of the protectors
Acquire Ashen Mist Heart
Discover an ancient covenant
Acquire the King's Ring
Defeat Looking Glass Knight
Reinforce a weapon to its limit
Light the primal bonfire in the Iron Keep
Discover the clangorous covenant
Light the primal bonfire in Brightstone Cove Tseldora
Inherit equipment from the head of Vengarl
Give Rosabeth of Melfia something to wear
Light the primal bonfire in the Black Gulch
Discover the covenant of rodents
Discover the covenant of the fittest
Light the primal bonfire in Sinner's Rise
Defeat the Last Giant
Discover the covenant of the meek
Die for the first time
Reclaim flesh and set out as an Undead
Earn all achievements
Defeat Vendrick
Learn all sorceries
Learn all miracles
Learn all pyromancies
Learn all hexes
Increase the population of Majula
Inherit Benhart of Jugo's equipment
Inherit equipment from Lucatiel of Mirrah
Inherit Steady Hand McDuff's equipment
Inherit Laddersmith Gilligan's equipment