Here is the full list of all 27 The Last DeadEnd achievements.
100 headshots were made
Many enemies were killed by explosion
Killing via auxiliary subject
Cyclop was defeated
50 headshots were made
Drudj was defeated
Gulyabani was defeated
All wall texts were read on "Shirvanshahs' bath houses" level
10 headshots were made
10 enemies were killed by Axe
10 enemies were killed by Makarov
Shotgun found
Nagant found
Positive ending was chosen
Bad ending was chosen
The whole encyclopedia became available
Dark sinner was defeated
Last enemy was defeated
10 enemies were killed by Nagant
10 enemies were killed by Shotgun
10 enemies were killed by Sword
All wall texts were read on "Alleys of Old City" level
All wall texts were read on "Catacombs" level
All wall texts were read on "Sabail Castle" level
All wall texts were read on "Streets of Old City" level
All wall texts were read on "Road to the Maiden Tower" level
All wall texts were read on "Maiden Tower" level