Today only, Nov 19, 2014, ustwo Studio Ltd has Monument Valley for Android in the Amazon AppApp Store for FREE (regularly $3.99) for a limited time.

In Monument Valley you will manipulate impossible architecture and guide a silent princess through a stunningly beautiful world.

Monument Valley is a surreal exploration through fantastical architecture and impossible geometry. Guide the silent princess Ida through mysterious monuments, uncovering hidden paths, unfolding optical illusions and outsmarting the enigmatic Crow People.