It's my all-time favorite piece of music It is horizontally very difficult, and there are lots of voices in the piano writing, from the very beginning. So hard to make them all individual and working together, legato, not vertical sounding, etc.Virtuosity is also a concern: The octaves are quite awkward, the arpeggios in the coda are also kind of awkward.
Times are a-changing. Last year that last word would have become "pregnant dog"...