Here is the full list of all 24 Sweet Dream Succubus - there are Nightmare Edition achievements.
Beat the game in 3 loops
Get all 3 endings.
Get the succubus master ending.
Get a girlfriend
Solve her identity, her kind and her goal.
Get looped by a movie.
Discover her full name
Getting the hotel event
Get killed by the succubus.
Get to credits screen.
Discover her second name
Get all events
Getting the church event
Making the shady guy talk.
Skip a shower.
Getting the movie event.
Getting the library event.
Discover her first name.
Getting the delivery event.
Starting a game loop.
Wear a condom!
Get the clinic event.
Getting the Jog event.
Starting a new game for the first time.