There is potential here. The mechanic to match the theme isn't there with the single combat in the prototype. I can see how it would be interesting to ration the different spells and combos you have.
The UI leaves a bit to be desired. I wish there was a list of spells I already picked, or some marker on the already existing buttons. I could also pick duplicate spells (e.g. Scald + several copies of Ashes). Is that intentional? For some reason I had to click on spells that were marked as passive.
Shame it was incomplete for the jam, this could be a solid game!