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