A group of people are trapped in a sort of cannibalistic, punk rock city. There's one part where all the citizens are in an open area acting crazy and they burn and eat outsiders. The group gets caught but escape in a car they find inside a storage container in or near the city. It was a pretty weird movie and if anyone can help me figure out what it is I'd appreciate it.
That sounds like Neil Marshall's Doomsday
: partly filmed in Cape Town, although you wouldn't say it.