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...
Preview the start of Seduce Me 2: The Demon War!
Be Baptized by Angels.
Obtain True Power.
Impress the House Party Guests.
Rename the Main Character.
Find Harold Anderson's Magic Books.
Start your Adventure with Diana.
Get Shot in the head by Malix.
Get Proposed to by Andrew.
Obtain True Freedom.
Be Eaten Alive by Diana's Pit Beast.
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.
Kiss Erik under the Moonlight.
Get Proposed to by James.
Turn down sex, but keep your true love.
Unlock the Second Set of Bloopers!
Fight Malix Yourself.
Unlock the First Set of Bloopers!
Dodge Malix in time.
Prologue Completed!