Here is the full list of all 39 The Medium achievements.
Survive a monstrous encounter.
Find a note from a troubled man.
Inspect 100 objects in a single playthrough.
Burn through the moths using Spirit Shield.
Acquire the razor.
Find a page from a mentor's diary.
Reconstruct a Memory Shard.
Meet Sadness.
Find an Echo of a mysterious caller.
Find an Echo.
Reach the hotel.
Inspect 50 objects in a single playthrough.
Use Spirit Blast to create electricity.
Find a postcard from the groundskeeper.
Send Jack's spirit away.
Inspect 25 objects in a single playthrough.
Feed the cat in Jack's apartment.
Experience your first vision of Thomas.
Send the Childeater away.
Find the Red House.
Experience your second vision of Thomas.
Send the Hound away.
Uncover the mystery of the burned down house
Make it through the pump station.
Complete the broken mirror.
Finish the game.
Use Insight for at least 15 minutes.
Find all Echoes in a single playthrough.
Reconstruct all Memory Shards in a single playthrough.
Find all pages from Richard's diary in a single playthrough.
Find all of Thomas' notes in a single playthrough.
Find all of Frank's postcards in a single playthrough.
Find all of Henry's Echoes in a single playthrough.
Spend 10 minutes outside your body.
Escape the creature without alerting it.
Acquire the bolt cutters.
Use a mirror to cross over.
Defeat the creature in the flooded ruins.
Run 2 kilometers.