I think this game is quite clever.
I'm curious how you programmed the spells. I.E. tracking different mouse movements and mouse movement patterns.
The combat is ok, but seems a little too simple and redundant. Shooting spells that have somewhat different projectile behavior at enemies that move around randomly isn't super interesting imo. There isn't much variation or difficulty scaling with this system and most fights will feel very similar after awhile.
One suggestion would be to have enemies designed so they are susceptible to certain spells and immune to others. In order to defeat them, one must use the correct spells or combinations of spells. - This adds more of a skill element to the game, allowing more difficulty scaling, and gives the player a strong reason for learning and practicing different spells.