I'm suprised how they did it...
I would have tried with magnets myself... I think his design would break after a good set of wacks.
So I see 4 electro magnetics attached to a lever that would lift the moles. Then each mole would have a button on the bottom attached to a heavy spring. So that the lift from the magnet wouldn't trigger the switch, but a good wack should.
In the picture... left side is lift whole area... right is closeup on button... Its missing the heavy spring around the button because its too hard to draw in MS Paint.
Then you just need to turn on and off the maginets and your good to go...