NO BACKUP

1. 
   She’s Alive.

   Rescue Sarah Reeves.
   38%
2. 
   Gotcha!

   Scare off the alien by shooting it.
   75%
3. 
   Too Loud.

   Alert the alien 10 times.
   51%
4. 
   Lights Out.

   Let the entire parking level lose power.
   48%
5. 
   Wrong One.

   Scan 10 incorrect license plates.
   22%
6. 
   Jackpot!

   Find the correct vehicle on the first try.
   10%
7. 
   Improvised Access.

   Use the axe to break into the security room.
   17%
8. 
   Silent Operator.

   Complete a mission without firing a shot.
   0.3%
9. 
   No Backup Needed.

   Finish a mission solo.
   1.2%
10. 
    Marathon Runner.

    Complete a mission under a set time limit.
    2.9%
11. 
    Untouchable.

    Finish a level without taking damage.
    2.9%
12. 
    Still Breathing.Secret

    Steam withholds the description of a secret achievement.
    37%
13. 
    One More Cup.Secret

    Steam withholds the description of a secret achievement.
    7.7%
14. 
    Headshot Only

    Reach 25 headshot-kills without missing in the zombie minigame.
    0.1%
15. 
    Detonate.

    Activate the underground self-destruct and extract the blueprints.
    8.6%
16. 
    Handle This!

    Stun the witch your first time.
    47%
17. 
    Sherlock

    Collect all the evidences in the mansion and escape.
    16%
18. 
    Must've been the wind

    Complete a mission without being seen at all.
    0.6%
19. 
    Special Operator

    Rescue Sarah in expert mode.
    0.7%
20. 
    Security Officer

    Get out of the underground alive in expert mode.
    0.6%
21. 
    Ghosts? Bring them all here

    Collect and escape with all evidences in the mansion in expert mode.
    0.6%
22. 
    What Father Built

    Read every document left behind in the Blackwell Estate.
    13%
23. 
    Concrete Grave

    Whatever happened down here - now you know.
    4.8%
24. 
    Subject Zero

    Access the files they never meant to be found.
    47%

Names, descriptions and icons are the game’s own, as Steam publishes them; the share is how many owners have unlocked each, from Steam's global figures for 24 of them.