Here is the full list of all 22 Lust from Beyond: Prologue achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Finish the game.
Collect all the ritual items.
Read all the letters concerning Mabel and complete all the conversations with her.
Pick up all the items in Theodore's room.
Don't show any doubts speaking to the Cult members.
Finish the dream about the land of Lusst'ghaa.
Talk to the prisoner under the stairs.
Walk through Lusst'ghaa without receiving damage.
Look at unconscious Mabel for 3 minutes.
Look at the cultist orgy for 5 minutes.
Spend a minute reading prayers from Iauv'abrarc's altar.
Collect all the lauv'abrarc figures.
Open the secret locker in Theodore's bedroom.
Pick up the devil mask, when the light is out in the mansion.
Open the tabernacle with as few moves as possible.
Pick up all the masks.
Read all the notes.
Find and use all the first aid kits.
Find and use all the sedatives.
Pick up all the touchable items in the game.
Complete the game in censored mode.
Turn of censorship during gameplay.