This is a very fun game. Well done. It is extremely hard but still a blast. One suggestion would be - if you select a spell with only one possible option, just auto-apply it instead of making the user click anyway.
Glad you like it! I've experimented with auto-selection when appropriate. People were more likely to get confused about how the game worked when it auto-selects the only available target. Probably that should be an "option" you can enable so it doesn't confuse new players, and experienced players can turn it on to speed up selection.
Great point - my first 2 hours playing it would have indeed been confusing but hour 3-4 is when I started thinking on it. In fact those first 2 hours I thought focused spells were not just 1 focused per round, but one focused spell meant it was the ONLY spell that could be cast. So I missed a lot of damage in those early games. I figured that one out tho!