A world that is besieged by the lawlessness of narco-traffickers is pretty brutal, and this is a brutal, unflinching film about this reality. I found the script to be a bit unbelievable--not with respect to the demise of civil society and the corruption of power at all levels, but with respect to the credibility of the plot--but the film is powerful as a document of real social conditions, and also as a thriller.
This is definitely the Cannes discovery this far. An impeccably directed and very very powerful Mexican film – with some of the most fitting, brilliant cinematography I've seen in years. Also, the original story and strong main character is continuously edge-of-the-seat engaging. Flawless, unmissable film.