Where to start with this one? It had potential, the acting was mostly OK but the shot selection by the DP was terrible, the CGI was laughable and consistency was just not there in the behaviour of some of the characters. And as for the ending? That annoyed the shit out of me. You see two alternate endings one after the other without any explanation. Piss poor.
So, to the movie? Six friends meet up for a weekend away at one of their parents' houses. But a terrorist organisation fires a ballistic missile with a chemical warhead at rural America, somewhere near Baton Rouge. The chemical turns the locals into rabid crazies, the titular demented, who want to beat anyone they see to death. The 6 then have to escape, and then find salvation.
It had a few good moments but that ending did me in. The bad outweighed the good, and I couldn't give it more than 4/10, which is still better than the 3.8 on IMDB and Amazon and the 7% on Rotten Tomatoes.
Maybe watch it with low expectations.