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