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