Similar idea to what I had (you're the boss instead of the hero), but a VERY different execution :D
Loved the art style.
It took me a while to figure out that I needed to design the spell for the next round, as i was wondering why it didn't change actively and I'm still not sure what causes the spell to swap to the next type. Once I made something completely useless that didn't even reach the hero... whoops. :D