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