You've been enslaved by the goblin empire and need to by back you're freedom. (10,000.000c) you can buy upgrades at the goblin stall, each upgrade will give you a different amount and will cost a different amount. To sell your rocks, click S at the stall, and to open the upgrades menu, click B at the stall. You can move around with the right and left arrow keys, to mine, touch the rock and press space, and you'll notice that the pot hanging from the roof's number will increase, showing the amount of rocks you have, and each rock sold will give you a coin. you will also notice that by going into the shop, there is a number under each upgrade, showing the amount of that certain upgrade you've bought.
BTW, this is literally just a fancy clicker game.