The game was somewhat fun, and had a good concept, but there were a few things that I would change:
1. I would allow the player to change spells, whether that be by picking up items in the game, or by selecting the spells in the start-up menu, to increase replayability
2. I would make more enemies - not increase the spawn-rate, just make some diversity. It doesn't even have to be a whole new enemy, just different colors of slime. Seeing the same green slime spawn every time can get boring after a while - remember, replayability requires diversity.
I would also like to point out that this game has the same name and concept (a top-down shooter in which you cast spells to kill enemies - yes, it's a very common concept, but still) as a project that came before it. The name was changed, but it was still one of the first projects to appear in #jam-updates on the discord server, so please, in the future, if you are thinking about a certain name, please make sure that it hasn't already been used.