Really enjoyable
Well if you really improvised the melody you really have good improvisation skills - I loved the melody especially in the beginning.
The whole track was really enjoyable and kind of relaxing. I see a tendence on the AP's classical section that a lot of artists are starting to submit a lot of music like this: a solo piano piece. And they getting better and better.
Like yours. I don't really have any negative critics with this track. Nice and relaxing piece with good chrod progression - congratulation!