Right, people have been talking about coding on the timeline and whatnot, but really if you want to make a big game, you want to use Flash's object-oriented nature. It makes it much easier to expand your game, because each element is self contained and once you've coded your tank, for instance, you don't need to think about it again...
Coding like this is pretty confusing at first, but I'm making a series of tutorials explaining how to do it, here:
www.flashgametutorials.blogspot.com
you need some understanding of programming in ActionScript 3 before starting - this isn't so much about learning how to program, but how to organise your code for bigger games.
So far I've got this far (I know, not much). A and D to turn, W to thrust:
Nope, programming in separate ActionScript files. You only use Flash for creating images or animations - all the coding is elsewhere. The tutorials explain how.
The advantage is that you can easily expand your game, and you have a much clearer structure.
