Great job! Really nice fun game! A lot of attention to detail! I especially appreciated the coherence of the different animations, the level layout switching, camera shaking, the small curvature you gave to the level layout, the fact that the game paused when the window game is not focused, and, of course, the base concept! It runs smoothly!
I playtested for a little bit and I was not able to find relevant bugs or issues. The only things I noticed are the following (based on the attention to detail you put in the game I think it's probable you already noticed them): 1) I found it a bit strange that the last path line reaming on the screen after the ball gets reset (on you died state); 2) in a level layout, a block barrier was super close to the level outline, I hid in the small corner formed with the level outline, in that spot the enemies (apart from red balls) could not reach me, then when a red ball killed me the ball-health got stuck at the big-black-ball animation state (after restart everything returned to normal, though I don't know if that layout and the animation issued was correlated); 3) the path line flickering bothered me a little bit (I think this can be a little bit hard to make it always smooth)
Super great job! One of my favorites!