Here is the full list of all 13 Reloader: test_subject achievements.
Finish game with Reloader mode.
Finish game with keeping concentrate over 50%.
Use tactical targeting.
Escape from the Building without breaking a lightbulb
Escape from the Building.
Execute close combat with injured enemy.
Switch new magazine when bullet in chamber.
Defeat three enemies with head shot in a row.
Defeat enemy with two shots to the body.
Learn how to reload.
Finish game with Bullet counter mode.
Defeat inhanced enemy with two shots to the body and one to the head.
Finish game without fixing slide back.