Great to listen to a performance of this piece. It used to be one of my war horses during my college years, but it's been a while

It's indeed a finger-breaking bear of a piece, and overall your performance is quite solidly executed. Especially impressive is the fact that you basically set it all down in one take. I certainly wouldn't worry at all about slips in a piece like this. I don't think anyone gets through unscathed, even Horowitz or Richter

While the basic framework of your performance is certainly intact, I do have some specific comments and suggestions for improvement. Forgive me if I'm overly verbose; I love this music
Promenade 1 and Gnomus: Nothing much to criticize here. You capture the noble, stately stride of the promenade nicely. I like how you dig into the keys on the Gnomus and bring to mind the grotesque, misshapen image of the gnome in the pesante passages (at least I think I remember it that way from the picture

) Interesting piano variation on the repeat and good observance of the rests. Nice gliding legato in the accelerando passage and trills, and I really admire your ending for not rushing through it. So many pianists fudge the notes in the culminating passage. IMO though brief, this has to be one of the most physically taxing and clumsy passages in all piano music. You really get the con tutta forza element as marked by Mussorgsky. One small detail in the Gnomus that I noticed is in the last note of the measure right before the first
Vivo, you play G-flat instead of F? Maybe your score has it like that though, and Mussorgsky had so many alterations that he covered with ink strips
Promenade 2 and Il Vecchio Castillo: Here I think you could be a little more delicate and have a bit more rubato and rhythmic interest. It just starts to sound a bit pedestrian to my ears after a while. The promenade could be more sung and legato, and above all softer (some una corda could help in dashes) In Il Vecchio Castillo, the dotted rhythms, while not exactly cheated, could have a bit more retention. Part of the problem may be that the tempo is just slightly on the slow side (it's an andantino, but yours sounds more like a largo to me). Two small details I noticed is that in the third measure of the promenade, second chord, something sounds wrong (G-flat instead of G natural for the middle note?). Also, measure 15 of Il Vecchio, on the G-sharp, I think you play a quarter-note instead of two rests following by an eighth note (at least in my edition).
Promenade 3 and Tuileries: Again, nice pesante aspect of the promenade. The Tuileries is one tricky bitch of a piece, at least the way it's written. I resorted to all kinds of cheating myself when I played it

For instance some of those inner voices can be played by the left hand reaching over, and it does sound like you already do some of that. Your initial tempo is good, I think, but then it starts to get a bit bogged down and labored in places. The main thing I think you could do is lighten up and capture more of its carefree, childlike spirit. Toward the end, there are a couple of struggled passages where you slow down. Those are damn difficult the way they're written though. Are you using the left hand to grab those? And the chromatic-like scale is a bit flubbed and pedalled. Nice elegant ending though. I would find it more convincing if you could relax like that for the rest of the piece.
Bydlo: This may be my favorite of the set for its distinctly Slavic feel. One thing I've always wondered about this piece is regarding Mussorgsky's markings. You play ff as indicated but it seems that the piece has nowhere to go then by the time you get to the con tutta forza. Personally I would favor starting out more mp and make more of a crescendo so it all has more meaning. The score seems so bereft of dynamic markings that maybe we can add a few of our own in this case? Another problem with playing ff in the bass at the beginning is that the melody can't sing, In yours it sounds rather drowned in the texture. Maybe the melody could be ff and the bass mp-mf. Also the rhythm sounds just a tad jerky in places: I think the ox-cart needs to be more steady. Nice dynamic setup for the con tutta forza, however, and great whispering fadeout and ritard into the perdendosi.
Promenade 4 and Chicks: Nice handling of the tranquillo aspect at the beginning of the promenade. It does seem a tad on the slow side to me, and the lefthand octaves might be a bit overly serious and blurred with pedal. Nice subito lead-in to the chicks. The chicks is quite well played, very even, accurate, and clear, no mean feat. It could perhaps be lighter still even though it does sound like you're using the una corda. Nice graceful trills in particular. Overall, very well done.
Samuel Goldenberg and Schmuyle: Some of the rhythms here, especially the dotted ones, seem as though they could be a bit more precise. The triplet passage is clear, but the trills stick out just a tad perhaps. My main bone of contention is that there could be more rhythmic freedom, more of an attempt at capturing the scene -- rubato, ritards at junctures to pick up the contrast better between the hard-hearted Samuel and the pitiable Schmuyle (hope I didn't mix that up

). It all seems just a bit too straight. One rhythm that didn't seem right to me is the thirty-seconds leading into the final Grave passage. It sounded to me as if you played them more as sixteenths.
Promenade 5, Limoges, and Con Mortuis: Nice noble stride for the promenade once again. The Limoges is IMO the most difficult of the set. Quite an impressive tempo at the outset. It may be just a hair on the fast side, if only because you sag a bit later on in places, although you seem to notice it in yourself and pick it up again right afterward. Great mordant sforzandos in general. Those are really difficult to play in this texture IMO and you really drive them home. There is a strange-sounding hesitation leading into the repeated notes to the reprise. Is there a page turn there? The thirty-second interlocking chords leading into the attaca are a real doozy -- the single most difficult passage in the piece for me. I admire your relentlessness, but they do seem a bit loud and I might suggest playing them more staccato without pedal and just a bit faster. At a slightly faster tempo, they'll blend together so well you won't need pedal

Nice Dracula-like effect for the catacombs. In the con mortuis, the tremolos seem as though they could be a bit more rhythmic, lighter, and even in sound.
Hut and Gate: I hate to to say it, but this is the only part of your performance that I have more serious reservations about. The tempo is just too slow and the texture too turgid to get across the feroce aspect. I know you're probably being cautious for the sake of greater accuracy, but I think you need to go for the gusto and miss a few more notes especially since you miss a few even at this tempo. They'll be less noticeable at a greater tempo anyway.

Your sforzatos here in the lefthand octaves seem weak, which surprises me since they are quite good elsewhere in the set and a lot of the chords are too pounded and thick and thus lack the gruesome bite it seems Mussorgsky was after. The Andante section too seems too slow and fails to get across the ominous mystery. The Gate is much the same story. Too cautious and missing the grandness and heroism. Maybe it all just needs more time to mature.
Any reservations aside, I admire the masculine solidity of this performance and your taking on of this mammoth, craggy work, almost indisputably the greatest piece of Russian piano music ever composed. I know I've gone on way too long here out of enthusiasm, but I hope you find some use in my comments.
Joe