This is absolutely dripping with style and polish. Seriously nice work.
I only managed ~6k score and that felt like a decent go of it. I wasn't quite able to suss out the multiplier, I'm assuming from the description that I need to chip down multiple enemies to 1 hp and try to chain / multi-kill them to boost the score?
That might be the only thing that is missing, as everything else felt extremely intuitive and well designed. I like that the core game loop was about 2-3 mins per run for me, which feels like the perfect length of time for a jam, and I can then choose how far to take it.
The art is excellent, you've taken really simple assets and they just pop so well through the shader use and general art direction. The UI stuff is stunning, and really hard to get looking that good in my experience!
I enjoyed this thoroughly, thank you.