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...
Start your Adventure with Diana.
Obtain True Power.
Be Baptized by Angels.
Preview the start of Seduce Me 2: The Demon War!
Get Shot in the head by Malix.
Obtain True Freedom.
Be Eaten Alive by Diana's Pit Beast.
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.
Share some Cake with Matthew.
Accept Sam for the Man he is.
Kiss Erik under the Moonlight.
Impress the House Party Guests.
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!
Dodge Malix in time.
Prologue Completed!
Rename the Main Character.