Here is the full list of all 25 Seduce Me the Otome achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Witness Simon's Transformation with Diana and someone special...
Preview the start of Seduce Me 2: The Demon War!
Rename the Main Character.
Impress the House Party Guests.
Get Shot in the head by Malix.
Be Baptized by Angels.
Find Harold Anderson's Magic Books.
Be Eaten Alive by Diana's Pit Beast.
Start your Adventure with Diana.
Obtain True Power.
Obtain True Freedom.
Get Proposed to by Andrew.
Go To Paris with Naomi.
Prove Your Love to Suzu.
Fight Malix Yourself.
Give Damien his Humanity.
Share some Cake with Matthew.
Accept Sam for the Man he is.
Kiss Erik under the Moonlight.
Dodge Malix in time.
Get Proposed to by James.
Turn down sex, but keep your true love.
Unlock the Second Set of Bloopers!
Unlock the First Set of Bloopers!
Prologue Completed!