i just called square-enix, and asked them about the screen-tearing und how to watch the intro.
they said, that the v-sync problem is not caused by the game, but the settings in the ms-dashboard. ich should call XB-Live support to let it fix. (ridiculous)
and about the movie, the only way to see it again is to deinstall und then reinstall the game!!!! this is really BS! why didnt they make it autostart after logging in like in the pc version!?!?!?
i really dont get it! (>_<)