Here is the full list of all 30 The Dark Pictures Anthology: Man of Medan achievements.
Chose all of the Head decisions
Chose all of the Heart decisions
Finished Movie Night
Finished the Shared Story
Found all Secrets!
Found all Pictures
Found all of the black framed Pictures
Unlocked Julia's Spoilt Trait
Maxed Conrad and Fliss's Relationship
Maxed Brad and Alex's Relationship
No-one survived!
Only the women survived!
Only the men survived!
Conrad successfully escaped on the speedboat
Everybody survived!
Completed the Solo Story
Calmed Junior down
Found all of the white framed Pictures
Revealed the name of the ship
Maxed Alex and Julia's Relationship
Unlocked Fliss's Arrogant Trait
Found 25 Secrets!
Unlocked Alex's Aggressive Trait
Unlocked Conrad's Humorous Trait
Opened the window without making noise
Completed 10 QTEs in succession
Julia accepted Alex's proposal
Conrad successfully flirted with Fliss
Unlocked Brad's Envious Trait
Beat the Training Dummy