Gratuitous, derivative, and a thorough waste of time I was very impressed by both of Marshall's previous films. Dog Soldiers was a very good addition to the often poorly served werewolf sub-genre and The Descent had some really good and realistic ideas for a horror film... until the cave monsters showed up and it went a bit further than necessary. Still, both were reasonably intelligent modern horror films that showed him to be a talent to watch.
I saw this as a free screening due largely Marshall's other films. After seeing it, however, I really wish I had passed.
It's little more than a mish-mash of much better films with little in the way of plot or character to fill in the moments between set-pieces and gratuitous moments: e.g. random topless girl, something blows up for no reason, something explodes in a cloud of blood... these occur left and right and entirely without reason or purpose. It blatantly rips off the plot from Escape from New York (a character is even named Carpenter in apparent homage), the set-up will be compared to 28 Days Later (though any "massive viral outbreak in Britain" plot will get that now), steals a lot of design and atmosphere from Mad Max and still manages to throw in some medieval nonsense in there as well.
Fight scenes were of the terrible, overly-fast, shaky-cam, quick-cut style making them a jumbled mess and none of the effects really felt that impressive. Almost none of the plot has any semblance of sense with almost every action occurring for little to no reason and characters being encountered so randomly that the writing doesn't feel quite good enough to even be considered lazy.
In all I really enjoyed most of the films this is derived from. Heck, I even enjoyed Escape from LA to a moderate degree. This, however, was a waste of time and money even as a free screening.