I really dig it, there's a lot of clever ideas here I think. Scoring based on how far away you are is such a cool way to create challenge, if one wants it. Having to literally go back and forth between picking up discs and throwing, spending additional time in this pixely hell...I absolutely love that. I also like when the last enemy goes berserk and starts throwing two more discs, that kept throwing me off for a while but in a good way! Or just how the game gets more and more mad, with big slow discs that just patrol back and forth, then those start shooting... :D All good stuff.
My main issue is that the game feels unfair - it's not, but it feels like it is. See, I really like the art style, but I find it hard to read while playing. It's often unclear how far away discs are, and sometimes you get hit when you feel you shouldn't. I think a couple of things would help. Having some sort of grid texture on the ground, combined with shadows below discs would help gauging the distance/position better. This game would also benefit from a lot of of invisible "helpers", just trying to be a little nicer to the player. For example making player's hitbox a bit smaller, or having an extra grace period after rolling, just for 2-3 frames. Just little touches like that, you know? Instead of thinking you died an unfair death, you'd get a lot of close calls without making it trivially easy.
I think otherwise you've got a really solid thing here! Good job!