I didn't like this film and I regret that I bought it, for many reasons, not the least of which is that I was deceived by the image and teaser on the cover of the DVD.
I thought I was buying a SF film about survivors of a nuclear war trying to go on with their lifes. This film however is something diiferent. The original cataclysm is barely shown and is never explained - we never learn what exactly happened. The whole story is in fact a study in the slow but certain disappearance of all social order and even purely human reflexes amongst a group of people who are trapped in a cage without exit (an underground shelter) and with dwindling food and water supply... The person in hazmat suit on the cover is relevant only to a small segment of the film, as almost everything happens in a couple of pieces underground.
The film is full of incredibly vulgar language - it seems that absolutely everybody speaks with the "F" bomb beginning every sentence. There are purely obscene moments of sexual nature (nothing to do with love-making). Excrements, menstrual blood, rotting bodies and swarming cockroaches, all play considerable role by moments. There are very graphic scenes of murder, rape and torture. In one word, this film has more in common with "Saw" franchise than with SF movies. This is most of the plot and of the scenario - and this film REALLY disgusted me.
I would rate this thing one star, if it was not for the last five minutes, which contain one pretty cruel but really intelligent twist, which I didn't see coming at all. I also must admit that actors did a rather good job and the cast is strong: Michael Biehn, Rosanna Arquette, Courtney B. Vance, Milo Ventimiglia and Ashton Holmes all did very well. It is however Lauren German (an actress I never heard about before), playing the main female role, who offers the best performance - she sure can act.
But other than the last five minutes, watching this film was for me personally a VERY unpleasant experience. My advice - avoid it, except if you really like films in which people torture, rape and murder other people in the middle of rotting bodies and crawling insects...