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