Some missable and some collectible achievements, and many details as yet unknown, but this looks to be a pretty reasonable set of achievements for a single player ARPG type game.
Difficulty does NOT affect achievements
1 missable achievements (plus 19 unknown)
Sign in with Steam or Xbox to track your progress, and:
Unlocked automatically at the end of the tutorial section when you 'go to sleep' in bed...
Take a ride with Doctor Swansea
Upgrade a weapon
Upgrade a weapon with a module
Let Clay live during your first meeting with him
Take care of Dorothy's fate
Eat 10 rats
You'll start encountering rats during chapter 1, when you see them scurrying around on the floor just look down and interact to munch on them.
Heal 10 citizens
Take care of Sean's fate
Embrace Clay during your first meeting with him
Upgrade a weapon to level 5
Take care of Aloysui's fate
Take care of Swansea's fate
Defeat The Disaster
Complete the game!
Turn a district to hostile status
Finish the game without killing any citizens. Yeah, this is very missable!
Save this poor plant with water
In chapter 4, you'll go to the West End district. In a building opposite Kimura Tadao's house you'll find the pure water. The building is kindof between West end and Whitechapel on the map, just under where the line curves back up to vertical.
Once you've got the water, the plant is in your office at Pembroke Hospital - water it. Then sleep for 3 or 4 nights. It should then have grown leaves - interact with it to get the achievement.
It is not yet known whether this achievement is missable - so aim for it when you get to chapter 4.
Find the recollection of Paulus Aurelianus
Turn all districts to hostile.
Gather all collectibles
There are 30 in total.
Weaknesses & Vampires: Fire and Sun: The first is in the safe room after the tutorial section, as you enter its in the back left corner on a shelf.
Find all off-hand weapons
Find all ranged weapons
Find all melee weapons