Hey! I saw your game on Mark's stream and decided to give it a try myself. First of all, I like your art a lot. Enemies, despite being simple blobs, look all different from each other, the player's character is cute, and animations look impressive.
It took me a while to understand what does "scaling down" or "scaling up" means, I wish there was some indication right after starting to hold LMB / RMB, because it was not really obvious to me until I tried to hold a bit longer and saw the cast animation :)
I wish upgrades picked up automatically. I haven't noticed them at first, and felt that there were not a lot of them at the beginning of the game, so initially the game felt a bit boring to me.
But overall, I enjoyed playing your game. I like that there are a lot of spells, and most of them have different use case. It was really fun! Great work!