Really cool idea, albeit I don't really think it scaled too meaningfully, I felt like loop 10 was easier than loop 1 in the end. I don't really think there was much of an issue with the controls as I see a few comments about, I think it's pretty intuitive from my end.
I think the fact there are so few enemies on the earliest loops means it can be hard to tell what you're actually supposed to do to level up. I spent the first two attempts hitting the meteor with the freeze spell thinking I had to do that a certain amount of times before I'd level up before I even noticed the smaller enemies that I could hit. I also don't think those colossus guards really proved a threat by the time they spawn in.