Like another reviewer wrote, "Could have been...".
I agree... in my opinion, the story had a lot more to go on. The twist in the end (if we can call it a twist, as it impacts none and less in the story), just makes You go: "Hein?! What?! Why?!"...
The 6 is because the movie, in the whole, is just one more... Jai Courtney's performance is OUTSTANDING!!!!! I never really cared much for the guy, but after this, he has my attention and well deserved congratulations!!!!!
In general, they all do well, but the story, the way it went, didn't leave much room for shining.
It's a movie to watch on a stupid Sunday afternoon, when You get that "Bah... tomorrow my life goes back to the crap it is" feeling... it will help with getting You distracted for a bit. That's all...