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.
Start your Adventure with Diana.
Witness Simon's Transformation with Diana and someone special...
Preview the start of Seduce Me 2: The Demon War!
Impress the House Party Guests.
Be Baptized by Angels.
Obtain True Power.
Get Proposed to by Andrew.
Go To Paris with Naomi.
Prove Your Love to Suzu.
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.
Turn down sex, but keep your true love.
Get Proposed to by James.
Find Harold Anderson's Magic Books.
Be Eaten Alive by Diana's Pit Beast.
Obtain True Freedom.
Unlock the Second Set of Bloopers!
Fight Malix Yourself.
Get Shot in the head by Malix.
Unlock the First Set of Bloopers!
Prologue Completed!
Rename the Main Character.