Hey Man...
Sorry - I've heard your recording, but I caught it just before I was giving a piano lesson, so didn't have time to reply... That plus the fact that I've never played this etude before, so I probably couldn't say anything really productive since I've never attempted this piece.
Although - one thing - I would build the climax (to the A, Bb, Db, octaves) more by pushing the tempo and then quickly holding back to give more drama to the piece.
I'd also probably echo the Db & G repeated octaves a bit more... the dramatic loud, then the repeated octave ones with more mystery.
But then again... I haven't played the piece, nor seen the music so it's probably just generic help that you probably already know.