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