Snow Scooter: A multi-level platform game - Page 8

 _root.onEnterFrame = function(){
	if(inPlay==true){
		checkForKeys()
		checkForCollisions()
		checkGame()
	}
}

This is pretty simple: If inPlay is true, the game checks for keys, collisions, and everything else. Well done. That covers basically all of the things in a multi-level game!