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