Here is the full list of all 28 Vampyr achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Eat 10 rats
Embrace Clay during your first meeting with him
Take a ride with Doctor Swansea
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
Upgrade a weapon with a module
Upgrade a weapon to level 5
Take care of Dorothy's fate
Take care of Sean's fate
Take care of Aloysius's fate
Take care of Swansea's fate
Turn a district to hostile status
Complete the game
Finish the game without killing any citizens
Defeat Fergal
Defeat Mary
Defeat Doris
Defeat McCullum
Defeat The Disaster
Turn all districts to hostile status