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