A small and inconspicuous looking horror film that starts off somewhat tepid and doubty, but builds up surprisingly well. The first 30 minutes are quite slow and the actors aren't really A-grade, which doesn't muster up too much confidence in the rest of the film, but stick with it and you might be surprised.
There's a feeling of dread from the very beginning, but because of the slow start it never feels like it's going to materialize into something tangible. That quickly changes once the film starts revealing its true nature during the middle part. Things get weird really fast and because the intro didn't reveal anything of note, you'll be struggling to keep up.
Brown really drives up the tension during the second half and keeps it alive until the very end. A mix of sci-fi, body horror and nature's revenge blends together to create a very creepy and disorienting atmosphere. Actors are pushed to the background and what remains is a moody and freaky horror film. Pretty good.