When Johnny is speaking with the school students highlighting the error of his ways, his hair has grown back. Nate stands at the back of the class, wearing his old glasses, but he has maintained his skinhead. This makes little sense in regards to continuity of his character.
When Nate is drinking with Angela in her car, Angela's car door shows it unlocked as is Nates,then a few seconds later it's locked.
In the movie, Daniel Radcliffe, is wearing the same jacket as Kevin Costner's character Crash Davis in Bull Durham.
When Nate is in Dallas Wolf's bathroom on his initial visit to Wolf's house, you can see the shadow of the camera on the doorway trim reflected in the mirror behind him as the camera moves in for a closer shot.
In the beginning, while being interrogated by Nate, the terrorist refers to the terrorist organization as 'Al-Shabab'. An Arabic speaker would pronounce it as 'Ash-Shabab'.
As Nate Foster is first driving into the new Virginia compound he clearly turns the wheel of his truck using the "feed the wheel" method taught to and used by British drivers rather than the "hand over hand" method taught to and used by American drivers... thus revealing that Daniel Radcliffe is actually British versus American like his character.