Here is the full list of all 12 Lust from Beyond: Scarlet achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Escape the theater by killing all the members of the Scarlet Lodge.
Solve the puzzle in the theater with the least number of spins.
Finish the game.
Escape the theater without killing anyone.
Listen to the recording from the voice recorder in a secret room.
Collect all voodoo figures.
Examine all objects containing text.
Finish the second trial.
Have sex intercourse for at least 3 minutes.
Finish the first trial.
Meet with Rhea.
Press the piano keys 50 times.