Using Booleans to Manage State
If ActionScript supports enums use an enum instead of the many booleans. If not, use a string with one constant for every state. It's also better than the booleans. For example:

...
else if (state == FADE_INT_ASDF) {
   state = CODE_OF_NEXT_STATE;
   gameState = GameState.READY;
}
...


If the logic was more complicated it would be worth implementing the State pattern.



If the booleans were replaced to an enum/string constants you can create a new setTimer function which could remove some code duplication:

private function setTimer(int timeout, IntroState/String newState) : void {
    var timer : Timer = new Timer(timeout);
    timer.addEventListener(TimerEvent.TIMER, function() {
        timer.stop();
        state = newState;
    });
    timer.start();
}