When I was a kid my first "game" was a powerpoint slideshow that was supposed to be Whack a Mole. Each slide was a drawing of the mole coming out of another hole and you were supposed to click it. Obviously it didn't matter where you clicked, it would move on to the next slide anyways.

since the hammer stays, if a bomb shows up on the same hole or behind it, it can be hard to see

I say all it needs now is more animation and perhaps some moles with gruesome sound effects upon hit.