Just gave your game a try and was very confused at first. I skimmed the description but it took me a minute to find a combination that actually did damage (found the fire trail first and kept doing that to survive).
After 2 rounds, one of just running flailing and dying, and a second of finding some success with the fire trail spell, I went back and fully read your description and also your GDD to see what I was missing. Knowing that you did this in just 7 hours is very impressive!
If I could suggest just 1 improvement, some form of tutorial would have been very useful. It wasn't until after I read the GDD that I realized I could double up on the same element for spells which makes sense now that I know it, but when I was trying out combos it never even crossed my mind to try.
This is the bones of something cool! I hope you keep working on it.