I listened to this and replied in real time. Sorry if some of my comments don't make sense, I couldn't find my score after all. Reading it over (I'm typing this after having typed the comments) it seems a bit on the negative side, but rest assured I'm impressed with the conception. It must be a new piece for you, and many passages are quite nerve-racking!
Good luck.
Theme - Beautiful use of the soft pedal, and also the voice -leading is great, esp.half-way thru. I like the relaxed, easy, timing. Overal good shape
Var. 1 - I am generally in favor of interpreting RAchmaninoff's markings conservatively; I think this is too fast, too soon. Also, maybe slightly too loud? The way he structured the early variations seems to pull us easily out of the mood of the theme, but yours is a bit too sudden, at least for my taste.
Var. 2 - Also could be softer, I believe... perhaps if it was slower, you would be in greater control of the notes in the middle.
Var. 3 - I disagree with your strong accentuation on the d minor chords, and think rather what it needs is a perky touch with a bigger space after it... the expression comes more from the timing and articulation, then a big accent.
Var. 4 - Great voicing, esp. the octaves leading into the single tones.
Var. 5 - Good timing, though I think it can be slightly, ever so slightly slower, so that each staccato is heard.
Var. 6 - The slower tempo may benefit this variation as well.
Var. 7 - Great piano playing! Thrilling!
Var. 8 - I really believe this is too fast. The music should rather slink along, like some kind of sensuous, dangerous cat. I love the way you contrast the articulation, and all the voices are audible in the right hand.. however it's too active, and should really be slower and more mysterious.
Var. 9 - As further evidence that the previous is too fast, you play this one, which should be faster, in the same tempo! But I think the tempo for this one, feels right.
In the mysterious middle passage with the octaves, the voice hidden in the Left hand thumb is not audible enough... I can see it was your intent, but I think it didn't come off strongly.
Var. 10 - Wonderful piano playing, very impressive, esp. at the very beginning, and at those runs with parallel tritones/fourths etc.
Var. 11 - You are adding an extra beat every other bar... I would only wait half-way thru, not after each two-bar phrase!
Var. 12 - Excellent!
Var. 13 - The 16th notes are not clear enough, and need to be articulated better... the character is not speaking fully as it is.
Intermezzo - Great fingers. I feel the main, ornamented melody is too heavy.. the volume may be right, but it doesn't sound like it is sung. I'm not sure about that last run, you may want to inspect the notes again...
Var. 14 - I would be careful not to rush at all, in general the feeling is right, but it gets a bit pushy towards the end of the variation.
Var. 15 - wonderful transition into this variation. As usual excellent voicing... how do you get it so clear? And with such a consistent, beautiful sound in the melody. Commendable nuance!
Var. 16 - Don't rush!! Esp. on staccato notes, and after the end-of-phrase flourishes. Great shape otherwise
Var. 17 - In general I like this a lot, there is a slight bit of rushing which mars an otherwise excellent approach.. perhaps it is just nervous energy. Did you mis-read the last note in the right hand?
Var. 18 - I think it's too loud, considering all the climax you have to build in the last two variations. Just take it down a notch.
Var. 19 - This can also start softer. Let the climactic moment come at the end of this variation, after that crazy right hand inferno, and then the fast chords..
Var. 20 - The volume that you have here, I think should not be used in the previous two variations, with the exception of the end of Var.19
This is one of those horrible passages that can go so horribly wrong (it doesn't here), but maybe some of the missed notes could be covered by more pedal? Just a suggestion
Coda - You can wait longer for sure before entering the rarefied world of this coda.
Excellent dynamics between the hands, and the shaping of the melody esp. in the highest range is beautiful. Excellent ending!
Walter Ramsey