After some thought, I remember that my thoughts went from "wow this is great" to "why isn't it ending?" about when the movie uses Hurricane Katrina footage to "date" the movie. It is kind of offensive to be sitting in a movie theatre, in New Orleans--where things are NOT fully recovered from Katrina--and watch footage of people on top of their roofs screaming for help.
After that things went downhill. Here are some bad reviews on the movie: rottentomato, and some other site that has obscenely strong hatred toward the movie