Here is the full list of all 15 Darkness Assault achievements.
Die 25 times
Make 500 shots
Make 200 shots
Die 10 times
Kill 25 enemies
Find Beretta 92
Make 50 shots
Find Glock 20
Kill 5 enemies
Kill your first enemy
Make first shot
Find S&W Model 625 MG
Read any document through game menu
Die 1 time
Launch game with Ultra Quality