Here is the full list of all 14 Conway: Disappearance at Dahlia View achievements.
Unlocked the shoe observation in every observation scene
Unlocked all secondary observations
Completed all character bios
Located all stamps in Dahlia View
Got a perfect score when playing darts
Caught the objects first time in Doerr Manor basement & in The Crow's Nest
Uncovered someone's true identity
Solve Downes evidence review without making any mistakes
Solved all evidence review scenes without making a mistake
Solved Doerr's evidence review without making any mistakes
Restored the Doerr Family Portrait
Dropped the box off the shelf in Levy's Garage
Solved Levy's evidence review without making any mistakes
Solved McKee's evidence review without making any mistakes