Currently it feels too slow, upgrades don't feel meaningful. Clicking with a few drones on screen feels like a battle, where you're both getting in the way of each other. Maybe drones could collect the stones so you can just click on the same place. Or they could give you more Stone/Clay while clicking gave more Sand? Just tweaks to incorporate them into the game, instead of being just a passive idle thing that barely does the same thing as you when you first opened the game.