This game is awesome. You can't just head straight in. You'll have to do some careful mining and aiming to make sure you can get back to the surface, and to get the most possible items from mining.
Pretty sweet zombie game! :D The only thing I would change is making the attack controls something that isn't under WASD. Other than that, this game is awesome. :P
I think you should change the prices on torches and trees. It costs 50 coins to buy a tree, but when you chop a tree you only get 3 wood, which gets you only 45 coins. So you'll lose money trying to get more trees, or you could just put wood in the shops for the same price as other building blocks.
Trees cost 10 coins