Goofs

When David is shooting his pistol at the range, the positions of the bullet holes in the target change between the close-ups and long shots.

The "government" helicopter David goes off to the NSA in has a registration number of N120MH, which is owned by a private company in Wisconsin.

A frame of a film is shown of a shooter on the grassy knoll taken at the time of the JFK assassination. The grassy knoll is in the background and the shadow is relatively long and goes to the right (west), indicating that it is mid-morning. However, JFK was shot at 1230pm so the shadow should be rather short since the sun is almost directly overhead and should go slightly to the left.