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.
Preview the start of Seduce Me 2: The Demon War!
Be Baptized by Angels.
Obtain True Power.
Be Eaten Alive by Diana's Pit Beast.
Start your Adventure with Diana.
Impress the House Party Guests.
Obtain True Freedom.
Get Proposed to by Andrew.
Get Shot in the head by Malix.
Go To Paris with Naomi.
Witness Simon's Transformation with Diana and someone special...
Prove Your Love to Suzu.
Fight Malix Yourself.
Give Damien his Humanity.
Share some Cake with Matthew.
Accept Sam for the Man he is.
Turn down sex, but keep your true love.
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!
Dodge Malix in time.
Prologue Completed!
Rename the Main Character.