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