Well-composed cinematically. The silence and documentary style evoke emotional and physical audience involvement, which makes the movie life-like and frightening!
Do not too close to the front of the theater. You can't see the diagetic time code. If you suffer from kinetosis, the camera shake will make you nauseous.
The ending diagetic date of the movie coincided with the real-time date that we saw it. Freaky. I know that after we got home and my cell phone went off in the middle of the night, I jumped farther out of my skin than a normal startle.