There is not much middle ground with this film.  People either loved it or hated it, with many film critics falling on the latter end.  I thought that it was one hell of an entertaining movie, with interesting characters, strong effects, a decent story line and some great humor.  The film was a product of the Project Greenlight reality show and was created by the show's winner John Gulager.
First off, I have always been a huge fan of Henry Rollins.  Having been a big Black Flag fan since the eighties, and a big fan of the Rollins Band and Henry's spoken word performances, I was interested to see how he would handle such a large role.  I felt that he delivered quite well, especially considering that the character that he played was a polar opposite of his image.  There were also strong perfomances by long time actors Balthazar Getty (Lost Highway, Natural Born Killers, etc.) and Clu Gulager (Return of the Living Dead, Nightmare on Elm Street 2, etc.).  Navi Rawat also gives a solid performance.
The beginning of the movie was unique and quite funny.  When it begins to show each character, there is a brief synopsis of the person given in text and more importantly, their life expectancy.  Creative and funny as hell.  Humor is used throughout the movie and was very well developed.
The story is quite simple.  Customers in a remote bar are stranded and a crew of monsters is about to attack them.  The bar patrons try to develop a strategy to fight them off.  Not all goes as planned and mayhem ensues.
The only disappointment in the movie for me is that you never really get a clear shot at the monsters in the film.  The creatures look very cool and it would have been nice to get better shots of them.  The entire creature is rarely seen and when it is, it is a very quick shot.  I must say however, that I enjoyed the fast pace of the movie which partially contributed to the fast action shots.
The gore is well done and used frequently.  There are a number of kill scenes and they are very well done.  There is no holding back on the blood in this one!
If you are in the mood for a bloody fight with some lighthearted humor to ease the tension, this one is a winner for you!