I'm already a huge fan of this game (got all the available achievements) definitely going on the Steam wishlist, can't wait for the full version. Out of the 2 characters in the demo, destruction magic is definitely the more powerful, but I enjoy that. The music is super catchy and the sound design is satisfying.
I'm hoping that maybe you could add challenge modes with restrictions, such as only having 1HP, or having bosses show up more often. Or something that would enable us to customize the run at the beginning, giving us self-imposed challenges or advantages. Also, I enjoyed the grind for all the achievements, and I hope that there might be more in the full version (possibly character-specific achievements?)