A bit more complete than John Popadiuk's KISS machine, but not by much.

I have a feel that the flippers are mechanically linked to the buttons.  There is no power in them.  Are the flippers weak because they are shooting pingpong balls, or are they using pingpong balls because the flippers are weak?

You're probably right there..Flippers look the same as those mini machines kids play to win a toy in a plastic egg