Great game. It's initially simple design in appearance, quickly became quite ingenious. I love the idea of the ball growing and powering you up, but restricting movement backwards at times. To begin with, the movement when landing on the platform seemed a bit ... I don't know ... unresponsive or sluggish, but when I got used to it, I loved how you can stick to the platform and "climb" up the edge instead of fall off.
Nice choice of music. It suits the game. Reminds me a bit of the "Unravelled" soundtrack.
It is a pleasant twist on the Metroidvania genre, and I think it would be well worth developing it further. Great work.
(I did get stuck at one point, when the ball was quite large, and the camera zoomed back to show the whole room, but I went out a door off the side and the camera didn't follow. It was below the room where the Breakout mechanic was implemented I think.)