I have seen only more 1 movie directed by this director, and that was Seed. That movie was pretty tame and boring, this was an pretty interesting watch. There is no bright segment in this entire movie. From the start to finish it's just a pure black terror of a movie.
I can say that the acting for the most part is pretty solid. I can't really fault any of the actors. The story is thin as it is, 4 inmates, and they decide to horribly torture the weakest one, who was only in prison for 6 months for trying to defuse arrest, while the three other guys are in prison for serious crimes such as Arson.
The only negative i got for this movie is the lack of depth. None of our characters have any depth, as in instead of giving us at the end the reason why these people were in prison, maybe give us a 5-10 minutes long backstory about all 4 of these guys, what caused them to get in prison in first place. Also the fact that they said at the start of the movie, that the victim took his own life, it really removed the shock for the ending. I think that they should of cut off the hanging at beginning, because it weakened the ending. I think it would of been much more stronger if the ending occured without us knowing it at the start.
Ultimately i actually enjoyed this movie and it is a very interesting psychological piece into 4 different types of people. Also this movie the social aspect of it is not just in prisons, i think similar stuff occur outside prison as well.