Wow, I just played this demo, and I LOVE the flow of the game. I think the biggest part in that is the adaptive music system, since it seems to try to match engaging with enemies and such. When you stroll toward an enemy and combo them perfectly, while the additional instrument kicks in on the first hit you do is just phenomenal.
One thing I noticed was that I sometimes thought I could jump up a ledge on the bottom of my character even though it was a wall. It is much more obvious when the side or bottom of the wall is visible. Maybe there's a way to indicate this better.
Another is sometimes when I tried to punch, it did not work. And I was not entirely sure why, so there is definitely potential for more clarity there as well.
Did you do the music yourself? Since you mention wanting "real artists and musicians" to work on it, but I really vibed with the track in the demo.