Yeah, but evidently playable with smart fingering and pedalling. I've spent time looking it over, and thinking to myself, "OK, this note to this hand, PEDAL..."
It's a Russian thing, I think - they turned out monster pianists (e.g., Richter, Gilels), and provided them with monster music, given that so many of their composers were monster pianist-composers (e.g., Scriabin, Rachmaninoff, Prokofiev, and evidently Stanchinsky himself).
In this particular case, though, the first movement is heartbreakingly beautiful in the hands of a pianist who can negotiate it. The virtuosity is less obvious without the score in hand: it's kind of like Bach's fugues in that it arises out of the needs of the voices. The kicker here is that this was written by a very young man - Stanchinsky died at age 24.