Exhilarating performance, absolutely thrilling! And like so much of Medtner it's a difficult work, yet you pull it off with delightful panache. May I ask how long you worked on this work?
You are way over-due for a recorder upgrade. When I worked as a music librarian/technician one of my duties was to record all student, faculty/staff, and guest recitals, and it was one of the most rewarding parts of my work, due in no small part to being funded for purchasing some very fine recording equipment (and several wonderful performance halls).
Initially, I used a gloriously warm (and big) Tandberg reel2reel tape recorder, and several sets of microphones to choose from. Sadly, after several years of producing some very fine recordings with this beauty, it was brazenly stolen, along with most of my recording equipment. But the silver lining in this tragedy was more funding, and this time I bought a new Sony Professional Portable Digital Audio Tape (DAT) recorder (at the time, it cost $2,500) along with some PZM microphones. This little unit, barely 6" x 9" x3" (deep) out-performed the Tandberg and was so small I could take it anywhere, and often did, on occasions when I was asked to record concerts off-campus, at other colleges and on several occasions at Lincoln Center.
My career came to a close in the mid-1990's and I have no idea what is available out there for the semi-professional audio technician, and I'd hardly expect anyone to fork out $2,500 but there must be newer technology that can do the job and doesn't require selling your soul. At the time DAT was a new format, and that Sony unit was a professional model. But seriously, a little voice recorder does no one justice. I really hope you (and some other people here in similar situations) find some way to upgrade your equipment, if only a little bit.
I would really enjoy hearing this Skazki, and any more Medtner you perform on something better than a dime store voice recorder!
I wish you well, and good luck hunting for a low-cost upgrade in the near future!
Lontano