Awesome, the practice mode has addressed my confusion! 👍 And now I have other thoughts...
Big potential here. The combination of attributes seems really interesting.
4 is definitely the right size board as it is now. Even 16 takes too long to consider all your options.
I'd love to see some means of combining two spells together (maybe with a chance it will either go right and make a crazy-powerful spell, or go wrong and ruin an otherwise useful spell).
This design _could_ work well with a touchscreen on mobile!