This was a fun arcade-style highscore game! (I got to 390 pts)
I really liked the artwork! The title screen was great, and the characters and enemies in game were cute. The "arena" could maybe use a little more detail/interest, but I suppose it keeps the action nice and clear.
Mechanics-wise, I liked the upgrades! I'm always a sucker for collecting coins and powering something up. I found the starting fireball to be my favorite weapons, but perhaps the others could be useful with practice.
I'm not quite as big a fan of the uncertainty principle part of the game. I didn't understand what was going on until I went back and read this page. Getting hit randomly doesn't feel great in an action/arcade game that plays around skill. It's an interesting idea, but without a clear way to counter it, it feels unfair.
Overall, I enjoyed this one quite a bit! Nice work!