Here is the full list of all 21 Oneiros achievements worth 1,000 gamerscore. It takes around 1-2 hours to unlock all of the achievements on Xbox One.
oneirOS activated
Found every game in the room
Watch every movie in the cinema
Find every anatomy book in the game
Flush water in toilet at cinema
Finish Unicorn game
Fix Chevrolet
Catch rat into the cage
Charge battery to max capacity
Make a fuel
Leave the room
Escape from island
Finish the game
Reach second island
Convince the bird to give you his nest
Open every cipher lock
Reach 5000 points in MiamiSkate3
Feed bird with all snacks
Find #1 egg
Finish game on machine at cinema!
Grab a bird from clock at the island