A bunch of Disposable Young Men are at a bachelor party. It's early in the morning and late at night, and things have gone beyond being controllable. They have just been kicked out of strip club and so go off in search of more trouble to get into. After some trouble on a subway they are left and marooned in the underground. Now as they try to find a way out they are menaced by barely human street thugs.
About one part "The Warriors" and two parts "Wrong Turn," it is a film of "civilized" men versus "savages." There is a lot of action in the dark, but do you really care if any of these knobs get out alive? I had trouble with it. Also, the underground thugs were only so interesting. I did like that they used dogs to hunt folks down in the transit tunnels. I also liked that at least one young idiot went out with a bang when he decided he rather hug the third rail than be slowly slaughtered.
For this genre, it's a middling effort. It's made well, it does have some actors that can do a decent line reading, and it does have a story that doesn't slow down for much. On the down side there's just not a lot of anything to make this different or more interesting than other stories like this. If you are a horror fan, it's probably worth a watch.