-About the flashing notifications, they're already taking up the full screen. You really don't need to flash them as well, they're impossible to miss lol. I'd remove the flashes altogether.
- The floatiness was in general gameplay, but it was more pronounced in the section you mentioned.
- I can see what you're torn about with the rings but it sucks a lot that you just die from it. Perhaps you should bounce off and/or lose HP from it instead of simply exploding?
- As for general control tightness, I can understand that being tough. You mentioned it was designed for controller and I was playing on KB+M so take that with a grain of salt.