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