Continuity: When Wade is at dinner with his family, when his stepdad is talking to him, Wade places his milk down on the table. Then in the next shot it is back in his hand, and then back down again.
Factual error: At the resolution of the movie when Filkins is sent back to Hong Kong, in the shot there is a banner written in Hiragana (one of the Japanese alphabets), not Chinese.
Revealing: Even though Drillbit's pinkie was supposedly cut off by the sword, you can see it is just bent out of sight.
Visible crew/equipment: In the scene where Filkins tries to run down the boys with his car, when he spots the boys coming from over a fence, as he stops the car, the camera is reflected briefly in the window. It becomes visible again as Filkins backs his car up.