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.
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.
Finish the game.
Listen to the recording from the voice recorder in a secret room.
Escape the theater by killing all the members of the Scarlet Lodge.
Escape the theater without killing anyone.
Examine all objects containing text.
Collect all voodoo figures.
Solve the puzzle in the theater with the least number of spins.