Here is the full list of all 18 Baba Is You achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Find an orb.
Complete the space area.
Complete the forest of fall.
Beat the game.
Complete the solitary isle.
Complete the ruins.
Complete the lake.
Complete the forest.
Complete the cavern.
Complete the mountain.
Complete the abstract area.
Complete the garden.
Complete a secret area.
Complete the world map.
Really beat the game.