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