Ha! You love on those descending chromatic progressions almost as much as me! You also like borrowed chords (especially the bVI and bVII), my favorites. And the bluesy IV7 chord around :44 is a nice touch. Ooo, and a borrowed iv later on. <3
Lovely chord progression beginning on the vi at 1:16. I wish you would have improvised around those 4 chords longer. They give such nice contrast, but they also follow the style of the chromatic decension you use at the beginning of the improv. My favorite part next to that is when you repeat the main melody in a higher octave at 3:26. That's another thing I like to do!
Really nice improv. The best thing about it is that you found a melody and came back to it enough that it felt like you had a direction in mind. I'd be interested in hearing one of your really adventurous improvisations sometime. :D
I'll leave you with a fun exercise I like to spark creativity. Have someone else play four our five different random notes in a row on the piano (within an octave). Then use that set as a motif to improv around. Choose a rhythm for those notes. Try to fit harmony to them. It can be challenging, but I think it's really fun as well!