All these are well played, with confidence and technical ability. Although some of the flourishes in the Chopin Nocturne are a bit fumbled.
The improvisation seems nicely done to me, but maybe the improvisers here, or those who recorded arrangements of this song, may have something specific to say. Indeed we do not accept incomplete pieces like the truncated Bach prelude (well done btw, I am studying this one too, and have been for a long time, it's not easy). You make rather heavy weather of the middle section of the Chopin 55.1, and you play bars 52 and 56 in major key whereas they're notated in minor key (at least in the Paderewski Edition).
But there is a big problem here as far as I am concerned. The digital sound is truly unpleasant and off-putting in places (like at the end of the improvisation) and there's an unacceptable vibration throughout some of the Chopin Nocturnes. The 55.2 needs more work indeed, and your interpretation is labored and not wholly convincing. The Fantasie Impromptu sounds a bit better but it is rather wild and uncontrolled, and there are some bad cuts just before the end.
If you can bring more discipline and lyricism in your playing, and provide an acceptable sound, these will be good enough. You certainly have the talent but need to work on control and musicality.
Cutting out parts with mistakes is ok (I do it all the time, though I'm trying to quit
) but manipulating the tempo isn't. We consider that over the limit. I think this might be the cause of that awful vibration I hear in some places.