Brie Larson in Red Band Trailer for 'Free Fire'

This looks pretty nuts, right? With the Toronto film festival underway as we speak, this movie premiered to some pretty enthusiastic responses, with most calling it a violent, bloody, fun B-movie, which has to be all this was aspiring to be anyway, based on this trailer. The fact that it's a shootout all taking place in one room looks to me like it could get old fast (no matter how short the movie actually is), but who knows. I'd just need a little more of a story there.