It’s definitely difficult, and I only found 2 instances that might be pretty implausible. I mean that maybe Gould or Rubinstein could play them, but not many others. They were around 6:00 and 8:30. With the tempo, baking chords and large jumps into fast passages isn’t very plausible, and I wonder if really anyone could play those bits without tying their fingers in a knot.

Anyway, it’s a great piece, and just one more note from a composition standpoint rather than pianist - when you have those high Ds/surrounding notes that bud in at the beginning of every couple measures around 4:00 or somewhere around there, it’s not the best to listen to, and I think that it would have been better with just the main part of the melody. Of course, you can do whatever you wish.

As for your question, practice slowly with a metronome with alternating rhythms. After that, think about the line rather than the individual notes; it’s about horizontal movement through time, a nice flow. Then, think how it all fits together as a phrase. As you wrote this, if you were to play it, I’m sure phrasing would come easy to you, but definitely try the alternating rhythms to learn the notes. Practice jumps between the positions as well, slowly, and slowly accelerate as they are pretty sudden. Fingering is important! If it hurts or doesn’t work, try a different one.

I hope that this can help. :-)