This is one terrific movie, it wears it's influences on its sleeve with obvious references to shows like the Twilight Zone and The Outer Limits. Like the best of those shows the movie draws you in and somehow shocks you with the little things.
This is the best type of horror movie as you feel claustrophobic despite the wide open spaces of the American West and the monsters are more in your imagination than on the screen.
Watch this one with the lights off!