Filmed weakened by gross overstatement, pounding of audience

I rewatched MIA a few nights ago, except for the gruesome, nonsensical ending. I agree the girl's character belonged somewhere else. She was perfectly charming, but nowhere believable under the circumstances. I thought the scene for the BBQ was good, but the individual elements of the film simply don't hold together. Too many distractions that go nowhere. The film seems to depend heavily on the audience's "inherent" sympathy and understanding for these lost souls. That works, somewhat, until maybe about halfway through. It felt very contrived, manipulative, and the ending felt like a complete betrayal of anyone who continued to be engaged. I would love to know the director's and/or writer's thought processes, what exactly they were hoping to convey. And, though I admired Linda Hamilton's Sarah Connor, seems like her character was another dead end. What an opportunity squandered!