In the closing scene Archie is standing with the Sagrada Familia (Cathedral) behind him. Then he turns to a girl to light her cigarette and the Sagrada Familia is still behind him, even though he is now facing in a different direction.
During the fight at the end between Ray and Carter, the image is flipped. Ray's cast moves from his right to his left hand, the gun from the right to the left. When Carter shoves him through the door it is a left hand opening door. It is corrected when Ray comes back through the door.
During the climax of the film, Raymond fires 7 shots from a six-shooter without reloading.
Near the end of the film, when Carter is driving away in his truck, and Raymond is fighting him for the steering wheel, the gearshift is in the Park position.
In the scene where they are rattling off the names of comic books, "Marvel Mystery #1" is used. There is no Marvel Mystery Comics #1. It is actually "Marvel Comics #1". With issue number 2 the title changed to Marvel Mystery Comics.