I had a ton of fun with this. The spell variety is fun, the aesthetic is great, and the gameplay's super addictive. I'm gonna be playing more tonight to hopefully beat it.
The only nitpick I have so far would be with not knowing what mana what spells use - it might be beneficial to colour-code the spell icons in the wheel to show what type of mana they use. Either way, it's really fun and I hope you keep working on it. I'd absolutely buy it if you released it commercially.
I recorded my first playthrough, and you can find that here, whenever the video finishes processing: