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