Idea is really interesting and engages you to be creative a bit, but for me gameplay was really repetitive. When you find a strong combination of spells (ray + anything, basically) you just kill anything and dont have any problems. I would have liked if you had to cook spells on the fly and maybe if same spell shapes and effects had a small cooldown, but maybe I just love to torture myself with hard games, so don't bother)
Overall great concept, good art and fine soundtrack, very solid.