Here is the full list of all 56 Castlevania: Lords of Shadow 2 achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Complete the game at Prince of Darkness difficulty
Increase the Mastery Level of all weapons to the maximum
Increase the Mastery Level of the Shadow Whip to the maximum
Acquire all of the skills and upgrades
Acquire all of the Chaos Claws skills and upgrades
Acquire all of the Void Sword skills and upgrades
Increase the Mastery Level of the Chaos Claws to the maximum
Increase the Mastery Level of the Void Sword to the maximum
Gain a total of 100000 Experience Points
Acquire all of the Shadow Whip skills and upgrades
Annihilate Satan and save the world, again
Get rid of Zobek forever
Gain a total of 50000 Experience Points
Finish off Satan's second acolyte
Shed your darkest self
Gain the trust of Victor
Increase the Mastery Level of a weapon
Sabotage the Toy Maker's show
Defeat Agreus
Eliminate Satan's first acolyte
Subdue Carmilla
Survive the train trip
Gain a total of 10000 Experience Points
Buy an item at the Chupacabras' shop
Kill the Gorgon
Release the Chupacabras from his prison
Capture Raisa Vólkova
Acquire a skill
Destroy the golem
Accept Zobek's gift
Defeat the Paladin
Complete all the Reminiscences of Sapphire challenges
Complete all the Recollections of Ruby challenges
Complete all the Reminders of Amethyst challenges
Complete all the Memories of Emerald challenges
Complete all of the Kleidos challenges
Complete all of the Kleidos challenges at Prince of Darkness difficulty
Recover 30 Void Gems
Recover 30 Chaos Gems
Recover 30 Life Gems
Recover all the Void, Chaos and Life gems
Recover all the upgrades for the Relics
Collect all of the art
Spend a total of 20000 Experience Points at the Chupacabras' shop
Cook a chicken in the old style
Complete 110% of the game
Recover the Void relic in Revelations
Recover the Chaos relic in Revelations
Defeat the Lieutenant in Revelations
Complete Revelations at Prince of Darkness difficulty
Find all the Secret Boxes and Soldiers' Diaries in Revelations
Collect all the artwork in Revelations
Acquire all the Crissaegrim's combat skills and upgrades in Revelations
Increase the Mastery Level of the Crissaegrim to the maximum in Revelations
Kill an enemy with the Ballroom's saw in Revelations
Find those annoying characters from Alucard's past in Revelations