It's been a while since I've listened to this sonata, and what a pleasure it is to revisit the piece in such a performance as you've posted here. Hearing the first line is like visiting an old room...and really I don't know how to finish that thought..it's a nostalgia, maybe, but I don't want to call it that. I love very much this composer and to tell you the truth, I'd forgotten how much I loved the lonely-inward world of this sonata. There's really nothing nothing like it.
I could only wish you'd restrained the pedal a bit on the runs so there could be a clearer texture and a preserved line. It's just a bit muddy in those spots, though I think I understand your decision. Overall I love the world you create, and your understanding of the piece shows. While the structural understanding is apparent and logical, you've a very improvisational way which I've not often encountered...as if it's all sprung out of nothing, capturing an original thought on the mind of the composer, or the state of his mind in that moment, rather than his working out of the material to achieve the final composition (I've been up all night and am not exactly sure how to write that, but it is a compliment!) It all works well with what you say in the post above this one (which could apply especially to many other of his works...you are familiar with Wozzeck and Lulu?)
Thanks very much for this!