As some others mentioned already below, I have also some mixed feelings about it. I like the general idea of the game. Unfortunately I had a hard time figuring out how it works and failed multiple times at the mining level which was a bit frustrating. I made it to the second last level but I didn't know what to do then. Either the next level is not implemented yet or I just didn't understand what to do.
Some more explanation would help the game and I think it is a good start for something very nice! I really like your art style and the beautiful intro!