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.
Beat the game
Solve the Knight puzzle
Rest at a bonfire
Find the OUYA logo
Find your Dad
Find the Animax logo
Open the Wine Cellar passage
Find the Night Light logo
Set Fleur free
Find the amazing frog
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
Find the Secret Room
Escape the Catacombs
Meet Flying Hawk