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