Here is the full list of all 29 GYLT achievements.
Escape with Emily
End the Game without Killing Anyone (without bosses)
Escape with Sally
Hoop a can
Hit an enemy with a can
Escape with Both Sally and Emily
Escape from Helplessness
Freeze one Enemy of Each Type
Reach the Final Mine
Free all the Inhabitants
Get all the Diaries
Defeat Violence
Reach the Basketball Court
Try to Play other of Tequilaworks Game
Freeze an Enemy and Push Him
Access the Art Building
Defeat Exposure
Kill an enemy with a Stealth Attack
Get into the Theater
Defeat Violence in the Laboratory Without Being Hit
See the weirdness in the school
Escape from the Arcade without being detected by Exposure
Remove the battery from the Arcade core
Blind Three Enemies at the Same Time
Get outside of the school courtyard
Defeat an Enemy with the Flashlight Beam
Shock an Enemy
Enter the school looking for Emily
Use the Planks to Remain Dry