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