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