I love this Spell Casting Mechanic!
I had also the Audio Problems and sometimes the game crashed. (It was “Back to Menu” and “Upgrade Tower”.
Beside that. The Juiciness was really cool! The effects on the spell cast and also the camera shake were on point. That made the feeling very good!
As others mentioned, it was a bit hard to grasp what to do. I had esp. problems to understand that I can actually go “up”. After that I knew what to do and it was a fun game!
Also wanted to say that I appreciate your transparency regarding the assets! Putting them together for a good game is a big task itself and you did very well. The Audio was a good fit!
Really good job!