Good idea, bad execution. The rocks are worthless and just take up space, there should be something you could do with those. I like the bravery meter to go to more dangerous mines, but the pickaxe level should not determine how much you get, it should determine how your chances of getting rarer material. The coal burns up a little too fast. You should also be able to sell things back, like wood you don't need.
There should also be something telling you which stage of axe, shield and sword you have instead of just numbers because if you make a gold shield and forget and make a bronze one after, you loose your defense ability. It's a good idea, but it does need a lot more work. Right now it's just a medal collecting game. I have hopes for this so I encourage you to update it a little bit, no one wants their game to get deleted after a week to poor reviews and ratings. As it stands right now I'd give it a good solid fifty percent. (2.5/5)