Here is the full list of all 16 Midnight Mysteries 3: Devil on the Mississippi achievements.
Complete the Captain's lock puzzle.
Collect the skull from Joe.
Unlock Unlimited Hidden Object Mode.
Complete each HOG in Story Mode without the lantern.
Find all of them 80 bones in "Dem Bones."
Find all the boats in Deptford without a miss.
Find every hidden object in all Unlimited HO Mode scenes.
Complete Story Mode.
Solve all the puzzles in Story Mode.
Complete a hidden object scene in less than a minute in Story mode.
Clear the pool table in one shot.
Collect 100 clovers in Story Mode.
Complete the bonus chapter.
Collect all the ravens in Story Mode.
Complete Story Mode without using any hints.
Complete Story Mode with no Black Cat scares.