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