Audio problem: In the scene where the polite leader is addressing the Sandins for the first time he takes his mask off and starts talking to the camera but he is muted until James unmutes him. If you watch the polite leader while he is muted he mouths the words "Mr. And Mrs. Sandin" before he is unmuted. However when he is unmuted we hear him finish that statement by saying "Mrs. Sandin" again.
Continuity mistake: In the scene where Ethan Hawke is talking through the safety glass in the barricade to the polite leader of the gang outside, the leader shoots the loud-mouth guy standing to the right of him, using the pistol in his left hand across his chest. Immediately after that they show a top shot of him dropping his right hand holding the gun.