There's a decent idea buried somewhere in this film and there are fair performances from the cast. However, there's a big problem which lies squarely with the script. Taking ideas and plot lines from various other films does not result in a good movie. Nor does adding actors from other zombie/apocalypse films for no reason.
In short, a dodgy pharmaceutical company has tested 30,000 people with an experimental drug. Several weeks later, all bar one (Myanna Buring playing pretty much the same role she had in Neil Marshall's Doomsday) are infected with a zombie like disease which turns them into the infected from 28 Days/Weeks Later and gives them the ability to free run like that guy in Casino Royale. Remember that? That was good, wasn't it? I wish they'd make another Bond film. Daniel Craig is a great Bond...Anyway, where was I? Oh yes. Said dodgy company who aren't the Umbrella Corporation from Resident Evil (not at all) send hardman Craig Fairbrass (not related to the two guys from Right Said Fred) after Myanna to find out why she's not infected and if she possesses a cure. Meanwhile, Myanna's boyfriend Danny Dyer, his mate (Sol from Doomsday, the camper from the opening scene from Dog Soldiers and one of the Crawlers from The Descent - spotting a pattern?) and a couple of pointless characters are hiding in a garage/workshop probably belonging to the director's brother. Once everyone meets up, it's time to get to da choppa without being eaten.
Like I said, there's a decent idea in here, but it's lost in a mish mash of scenes from several other films and it's definitely not helped by the use of actors from other, better films. Seeing Sean Pertwee in this for all of five minutes just reminded me how great Dog Soldiers and Doomsday were.
Give Devil's Playground a watch if you don't have anything else available and you keep your expectations extremely low. Then watch Doomsday and 28 Days Later to see how it should be done.