I like this a lot. And since you mentioned constructive criticism, I'll give some.
- I'm sure you're aware that the music isn't the best, but I really respect you making it on your own like that. It's extremely daunting and better than what most people have or will ever make.
- I agree with the comments from akshay broadly, but I liked that the mana regen was slow since it forced me to understand that some of the spells like the red circle do a lot more damage than the fireball you get at the start. I do think that there should be more communication of that though, and that it should maybe be a smidge faster.
- I super agree with the idea of a controllable camera. I was surprised at how well it worked from a fixed viewpoint but I think that being able to look around in 3D space would be cool. You could even just yoink the fortnite approach to having a 3rd person camera with the player in the left third.
- All in all, I had a much better time than I expected once it got going. I died on my first run but succeeded on my 2nd, and it was a fun time all around!