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