During the shootout sequence at around 50 minutes. Adkins' gun changes from a Glock to a Beretta m9 repeatedly between shots.
In Mexico sheriffs don't exist, unlike in the United States. The closest equivalent in the former can be the chief of a preventive or municipal police force in a Mexican municipality.
The back of the Region 1 DVD erroneously claims the film costars Michael Jai White along with Adkins and Slater.
When Flaca steals the satchel containing the $2 million and is chased by The Man, she runs as if the bag is virtually empty. In fact, $2 million in 100s (at 497 US bills to the pound) weighs over 40 pounds, and the heavy satchel (about 1/3 of her estimated weight) would have slowed her down considerably. The weight of the bag would also have likely drawn the interest of the thugs who throw it at him (again, as if it weighs about 5 pounds).
During the car chase, "The man" all of a sudden in one scene changes gear in his Mercedes with his left hand, despite driving a left hand drive car (which has gearstick for right hand).
When The Man falls asleep and flashes back to his encounter with El Jefe, the sub machine gun El Jefe uses is obviously plastic as a mold seam can be clearly seen running the entire length of the gun from muzzle to butt stock.
When Chief Espinoza is sitting on the porch and aims his revolver at the passing dog, it is obvious the gun is not loaded since, in an extreme close up, no rounds can be seen in the cylinders.
When Adkins first walks into town with the dog, a wire that should be invisible as it keeps them together can clearly be seen in reflected sunlight during three different shots.
During the chase through El Fronteras there is a market umbrella that promotes a beer only sold in Bulgaria - Kamenitza.