Oh so close
I wish I could give this a ten. It fits almost all my requirements. Innovative, skillfully done, challenging, and, most importantly, fun! the only problem is that, as many people have already pointed out, the "pro" difficulty is far too easy. I think the best solution to this would be either add a third difficulty, say extreme, or intense, and make it what most people would consider impossible. Take the lowest scores you can see here and make that it, maybe even reduce those by one. The other option I see would be to make a scoreboard that ranks people on overall tiles used. With one of these functions to give the game a bit of replay and you'll have my 10/10