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