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