This is the 2004 Dawn of the Dead remake. It's terrible. Don't watch it. Sarah Polley deserves a better movie to be her default credit on IMDB.
See, this is a rotten movie that's not rotten in a new way. In fact, it's rotten in all the same old ways. Plus, I saw the version on the Sci-Fi channel, which means one character's dialogue was almost completely muted.
Incidentally, this was directed by Zack Snyder, who went on to do 300 and Watchmen. I hope he's gotten better. Or at least more interesting. Because this was full of random closeups and slow-motion shots of shotgun shells bouncing off the ground. Feh.