Here is the full list of all 28 Vampyr achievements. It takes around 35-40 hours to unlock all of the achievements on Windows.
Complete the game
Defeat The Disaster
Turn a district to hostile status
Take care of Swansea's fate
Defeat McCullum
Save this poor plant with water
Take care of Aloysius's fate
Defeat Doris
Upgrade a weapon to level 5
Defeat Mary
Take care of Sean's fate
Defeat Fergal
Heal 10 citizens
Take care of Dorothy's fate
Upgrade a weapon with a module
Eat 10 rats
Upgrade a weapon
Embrace Clay during your first meeting with him
Take a ride with Doctor Swansea
Go to the Shelter and rest …
Let Clay live during your first meeting with him
Find all melee weapons
Find all ranged weapons
Find all off-hand weapons
Find the recollection of Paulus Aurelianus
Gather all collectibles
Finish the game without killing any citizens
Turn all districts to hostile status