This movie should have been great.
The acting is great. The locations are excellent, as is the photography, editing and so forth.
The premise is clever, the opening scenes of the script intriguing, and the actions of the characters logical given the circumstances. A few scenes are riveting, and the sequence of events, at least for the first half of the movie, captures your attention completely.
My feeling is that the film was cut, to the point where we are left with only the basic storyboard. The ending is questionable, probably because there are missing pieces of information.
Hopefully, the whole film was shot, and someone will go back and re-edit the final version someday. Or perhaps I am filling in a script that was not revised enough - who knows? But my gut feeling is that this film could have been quite extraordinary.