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.
Complete the mountain.
Complete the cavern.
Complete the abstract area.
Complete the space area.
Complete the forest.
Complete the forest of fall.
Complete the ruins.
Beat the game.
Complete the solitary isle.
Complete the lake.
Complete the garden.
Complete a secret area.
Find an orb.
Complete the world map.
Really beat the game.