Here is the full list of all 27 Lust from Beyond achievements.
Finish the game without opening the Xu’thrar.
Kill every character important to the story whenever you have the choice.
Finish the game after opening the Xu’thrar.
Spare or save every character important to the story whenever you have the choice.
Beat Amanda.
Collect 5 items revealing the history of Demiurges.
Collect 5 items revealing the story of the Queen of Pleasure.
Get the Mask of Ughro’ecna.
Commit suicide due to low sanity.
Make love to Amanda in the Trinity Chamber.
Join the Cult of Ecstasy.
Beat Tim.
Watch the Scarlet Lodge cultist defecate for 3 minutes.
Collect 5 items revealing the history of the Scarlet Lodge.
Set off to rescue Lily.
Collect all lauv’abrarc figurines.
Meet Amanda Moon.
Find the room dedicated to Lust from Beyond Kickstarter backers.
Meet Dr. Austerlitz.
Play the Lust from Beyond: Scarlet melody on the theatre piano.
Collect all clow figurines.
Inspect every Dr. Austerlitz painting at the Desire Hotel.
Eat 10 candies.
Ask every possible question during your telephone conversation with Dr. Austerlitz.
Arrive in Bleakmoor.
Get rid of Victor’s fleshlight.
Finish the “Queen of Ecstasy” chapter.