Centralized update

When you get into game programming, the first thing you learned is that you should use a centralized update function triggered by your onEnterFrame event or Timer (AS3)/setInterval (AS2) event that in turns call game objects update. There are many benefits in having a single point of entry for update - one is performance and another reason is you want the ability to control what game objects receive update and when. For example, when you are pausing the game, all you need to do is one line of conditional statement in your root level update function to ensure all child level update functions stop getting called.