Here is the full list of all 42 White Day: A Labyrinth Named School achievements.
Forgive Me
Clear Very Easy Mode
Tired of Love
Complete the Ghost Collection
Encounter All the Ghosts in Yeondu High School
Hipocrisy
Clear Hard Mode
Collect All the Ghost Stories of Yeondu High School
Each Encounter is a Surprise
Woman living in a cabinet
Bathroom is Scary
Clear Normal Mode
Friendship
Arrive at the Bottomless Pit
Visit the Labyrinth
Experience Death 10 Times
Arrive at the Auditorium
I'm Perfectly Fine
Arrive at the New Building
Delicious Soy Milk
Arrive at Main Building 2
Head Ghost Has Nice Hair
Experience Death for the First Time
Enter Main Building 1
Experience Death 50 Times
Experience Death 100 Times
Clear Easy Mode
Clear Hell Mode
Clear Hell Mode 7 Times
Clear Hell Mode 10 Times
Truth
Dangerous Pleasure
Sincerity
You Are Mine
Hidden Love
Complete the Ending Collection
You Can't Do this
Flirt with the Girls
She Approaches from Afar
The Scent of the Bathroom is Becoming Heavenly
Hee-min, Still a Growing Boy?
Nothing Fazes Me Now