Watched this on DVD tonight and really enjoyed it. One of the best zombie films I've seen in ages (zombies in the sense of 28 Days Later, not Night of the Living Dead.) Some excellent performances and a well written script. The most scary thing, of course, was the US Government. That's far more frightening than any blood-crazy zombie/maniac. I'll say no more as I could easily include spoilers. The best thing I can say is: don't miss it.