Here is the full list of all 13 Dead Beacon achievements.
Reach ending A in normal difficulty
Visit all locations in the game
Try to open 'that' door from both sides
Get all syringes, equipment packs and demonic runes
Get 200 points or more in the pistol practice range
Slay all mannequins in the dressmaker's room
Reach ending A in hard difficulty
Reach ending B in any difficulty
Clear ending A in hard difficulty without saving
Clear ending A in hard difficulty in under 90 minutes
Get the obvious triple kill with the rifle in the day zone of the new wing
Beat Dead Beacon nightmare mode, proving yourself a master of these games. (Ending A)
Clear Dead Beacon’s Randomizer in Nightmare skill (Ending A) setting the enemy randomization type to Total, setting Randomize Soul Dagger to No and without saving.