Thanks for the report! Are you on a phone/tablet or a desktop? And which browser, and is your keyboard set to a non-English layout (or Korean input mode)? Please click the game once and try A/D or the arrow keys. I just added a focus fix, please try again.
Thanks for testing, and glad the keys work now! For digging: you have to HOLD the arrow key / A or D (or S to dig down) until the block breaks - a quick tap used to only play the hit sound and lose the progress. I just updated the game so short taps now keep their progress for a moment, and a tip shows up if you keep tapping. Also check that the drill is strong enough for the layer you are in (it says “Drill too weak” otherwise) and that you still have fuel. If it still doesn’t work, tell me which layer you are in and whether you are standing on the ground when you dig.