Overall I liked the movie.
Good plot and lots of tension and action but required a bit of deliberate effort to watch.
I didn't like the camera work much. It was too dark to track the action well, and the lights flickering on and off was a bit overdone. It was the director equivalent to chewing the scene. Some of the sound levels required that the volume be almost too high for comfort before whispered dialog could be made out more or less clearly. Having a good dynamic range for an effect is cool, but I don't feel like blowing my ears out or squinting to try to keep up with an "artistic statement." Just bring it down a notch out of the rafters and it would be a better flick.