The one button a flash game shouldn't ever use.
Tab. And what did you do? You made the the damn button the most important one of all (unless you like reloading after every shot). Now I can't get my fix of filling birds with lead and not go to jail, because in order to do so I have to press the button that has a function preventing it from being used in a flash game. Seven for theoretical fun and interest I'm sure i'd be having if I could get past the second level.