nice! Yeah that makes sense. We had a similar issue with a game in the past that was heavy "focus on the player" and the way we tackled it was to have the HP bar appear and dissappear until your health was less than half. That said, I'm not sure if that would work with how quickly the player moves, so a sounds signal is a good call. Maybe you could leave behind a "heart list" with remaining and empty heart slots that fades out at the point of contact? Not sure. Sound definitely works, but isn't super accessible for people with hearing problems / if they wanted to play the game with low or without audio (late at night or whatever). Tough one to solve for sure!
But anywho, amazing work! A super solid entry and I had so much fun with it!! :D
and best of luck! Would love to see more!!