Hello, I played your game! :)
I was impressed with the overall polish, from the changing pitch and visual effect when you get hit, to the smooth menu transitions, and finally the character trail and overall visuals.
The mechanics feel unique and well-executed. It doesn't feel weird when the level shrinks (the character doesn't get pushed inwards, at least it doesn't feel that way). The way the player attacks by picking up the yellow circles feels nice too!
My only point of feedback would be that the character feels unnecessarily hard to control in the smaller levels. A lower maximum character speed in those levels specifically might have helped here. That being said, the movement speed in the boss rooms feels just right.
Overall, very, very impressive work. Feels almost too nice for a game jam spanning only 10 days.