I'm a bit torn on the movement mechanic. On the one hand, I really like the slingshot effect, on the other though I didn't really understand how to reliably use it. I also always tried to use it when on the circles, but later on realized it worked on the wings, and I'm not sure which was the best one.
I'll second that perhaps the movement could be improved a little, but I do really like the feel of it, I'd only suggest slight tweaks.
I had fun playing though, thank you for sharing your game!