The game crashed both times I tried to play it after a few waves. The game seems interesting, but currently seems a bit too limited.
Shooting doesn't feel that great, as it's hard to aim and there's no sort of feedback when firing or hitting something. The buttons are a bit hard to press, also you still fire the gun when clicking buttons on the HUD. I'm also not sure if the coin spell is useful as the game doesn't communicate anything about it to the player.
The healing spell also seems a bit too strong currently as you can simply wait for it to be off cooldown before starting the next wave. One way to mitigate that could be that have the next wave start automatically after a certain amount of time, as well as not letting you use spells between wave.
It would also be helpful if the upgrade gave some indication of cost, as well as if it's maxed out or not.
Overall, there's a solid base here, but it seems it could do with some more polish.