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 Power.
Be Baptized by Angels.
Get Proposed to by Andrew.
Get Shot in the head by Malix.
Go To Paris with Naomi.
Prove Your Love to Suzu.
Give Damien his Humanity.
Share some Cake with Matthew.
Impress the House Party Guests.
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.
Obtain True Freedom.
Get Proposed to by James.
Dodge Malix in time.
Be Eaten Alive by Diana's Pit Beast.
Unlock the Second Set of Bloopers!
Fight Malix Yourself.
Unlock the First Set of Bloopers!
Prologue Completed!
Rename the Main Character.