I found this on youtube its worth you time as a mapper
new things are
> events triggered by stand on it buttons (eg lift)
> events triggered by shooting something (eg rope holding bridge breaks as you shoot it)
> shoot boxes windows to destroy them
he gives a good all round evaluation of some of the more conceptual mapping ideas

[media]http://www.youtube.com/watch?v=FB1knvFYRj8[/media]