Some very good practical effects and make-up and some good gore keep this interesting. The cast and film crew try hard to make this an entertaining film but it has quite a boring middle section after a pretty decent opening sequence. If you are a fan of the genre you shall enjoy it, definitely has some decent moments but it just doesn't drag me along for entire ride.
One word of warning: this film is not for the squeamish -- there's loads of gore, be it alien or human. If you're not opposed to a little chunkiness, though, you'll find most of the messy parts here are pretty creative, especially one interesting bit about halfway through where our monster holds "Otis" hostage in ... an interesting way, to avoid spoilers.
Overall, nothing to call home about, but definitely worth the watch, and a recommendation to friends.