Here is the full list of all 43 CODE VEIN achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
View the "Dweller in the Dark" ending
Defeat the Skull King in the Gaol of the Stagnant Blood
Restore all Vestiges
Learn 150 Gifts (excluding those learned when acquiring a blood code)
Activate all mistles
Learn 50 Gifts (excluding those learned when acquiring a blood code)
Upgrade a Blood Veil to its maximum level
Defeat the Queen's Knight Reborn in the provisional government outskirts
Upgrade a weapon to its maximum level
Defeat the boss of the Crypt Spire, Juzo Mido
Defeat the Blade Bearer and Cannoneer in the Crypt Spire
View Murasame's memory echoes
Defeat the Successor of the Throat in the Crown of Sand
View Mia's memory echoes
Defeat the Successor of the Claw in the City of Falling Flame
Defeat the Gilded Hunter in the Ashen Cavern
Equip every weapon type
Defeat the Successor of the Breath in the Ridge of Frozen Souls
View Davis's memory echoes
View Io's memory echoes
Defeat the Successor of the Ribcage in the Cathedral of the Sacred Blood
Defeat the Queen's Knight within your memory
Execute a Communal Gift
View Yakumo's memory echoes
Defeat the Invading Executioner in the Howling Pit
Equip every Blood Veil type
Defeat the Insatiable Despot in the dried-up trenches
View Coco's memory echoes
View Louis's memory echoes
Defeat the Butterfly of Delirium in the ruined city center
Listen to partner conversations 50 times while exploring
Give a desired valuable to a friend
Defeat Oliver Collins in the ruined city underground
Successfully use a special drain from a parry, back attack, or launch attack
Unlocked all other achievements
View every ending
Explore every part of the depths
Receive 30 presents from friends
Raise your reputation as a companion to rank 30
Unlock the ability to inherit 50 Gifts
Collect every blood code
View the "Heirs" ending
View the "To Eternity" ending