Physics plays an important role in games since it defines behavior for the player, the world, and any items in the environment. Take that away, and you have a whole bunch of chaos on your hands.

Pam's Colecovision was her babysitter, from the age of 4 or 5, but the family only had one game. Over and over, hour after hour, she'd climb and jump through the three levels of Donkey Kong. But the ...