I had just a bit of time this afternoon, so listened to the Cm Impromptu. Very fine playing! When I played this piece quite awhile ago, I gave it a more of a romantic flavor, whereas I think your rendition leans more toward the classical sound. For everyone, Schubert tends to be a difficult composer to interpret, and where he was a transitional composer between Viennese Classicism and Romanticism, he can go either way (or both), and it's not as much of a chronological matter, but seems more related to his particular mood while composing a piece. In the opening the spirit there is actually alla marcia, although not marked as such, and I believe you established that well with your strict adherence to the dotted rhythms. You demonstrate control over the dynamics and shadings throughout the piece. I like how you play the Alberti figurations in the base while emphasizing the melodies. You varied the touches nicely. (In my rendition I took heat here for not playing staccato, but where there is a little staccato, the vast majority of those markings are played either pizzicato by tradition or portato per the notation, but I didn't feel like fighting it.
) There are some bass counterpoint figures which you etched carefully. At the coda the half-note octaves need to take on the sound of a trumpet, and you managed that too. This is a fine performance! Congratulations!