Here is the full list of all 20 Whispering Willows achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Set Darby free
Escape the Garden Maze
Escape the Trophy Room
Find the fox
Create a path for Elena
Set Flying Hawk Free
Escape the Basement
Escape the Catacombs
Meet Flying Hawk
Open the Wine Cellar passage
Set Fleur free
Find your Dad
Find the amazing frog
Find the Secret Room
Rest at a bonfire
Find the Animax logo
Find the Night Light logo
Find the OUYA logo
Solve the Knight puzzle
Beat the game