This game is really great and polished, i like the different upgrades, the difficulty curve was perfect and everything felt really nice. Could really imagine this to be one of these addicting mobile games that you play when you're bored. The sound and graphic is also really good, but the music is a little bit generic and gets repetitive really fast and i think some of the stones are a bit blurry. Besides that, great submission!
I hope my feedback helped you a bit, and if you have time, it would be nice if you could check out my game too! Thanks! :)