Factual error: In the scene when Will is opening the drawer of films from the Leeds home, there is clearly a copy of Mrs. Doubtfire in the left column of tapes. How can that be? Red Dragon is clearly set "several years" after 1980, as the caption says, but before the 1991 Silence of the Lambs, but "Mrs. Doubtfire" came out in 1993.
Continuity mistake: In the scene near the end where Graham and his son are trapped in the bedroom, the Red Dragon attempts to break down the door. After many forceful attempts, we see parts of the door jamb and moulding break-away and stick out from the wall. However, when Mrs. Graham enters the room after the shootout, the door jamb and moulding are in perfect condition.
Other mistake: When Dolarhyde is taking Reba to the zoo in his van, there is a shot of the road he is traveling on behind him. For the entire trip, he is driving on the wrong side of the road.
Continuity mistake: Before they reveal the face of the Red Dragon, they show him flipping through his book of newsclippings. He focuses on the face of the Tattler reporter and puts red markings through his face. When they show him closing the book, you can clearly see the face and the markings are noticeably different in the wide shot from the close up.
Revealing mistake: In the scene where Norton's wife is target shooting with the revolver, there aren't any bullet heads showing in the cylinder. There's also no recoil as she fires.
Factual error: In the scene where Will Graham is flying from DC to Baltimore to return the note to Lecter's cell, we see a panoramic view of DC and the Potomac River. We see him fly over the FDR Monument (located on the Cherry Tree Walk on the Tidal Basin near the national mall). Although that area was authorized a Park on September 5, 1959, the monument itself wasn't constructed until 1990 and was dedicated on May 2, 1997. It wouldn't have been there for him to fly over.
Factual error: When the FBI scrambles the helicopter to return the letter to Lecter's cell in Balimore, the camera pans across a scenic view of Washington. You see the famous sites - the Washington Monument, Lincoln Memorial and the US Holocaust Memorial Museum in the bottom right of the screen. Trouble is the Museum opened in 1993 and the movie is set before 1991.
Character mistake: At the very beginning of the film, when Hannibal Lecter is serving dinner to his guests, one diner asks "what is this divine looking amuse-bouche" when she and the other guests have a full plate of food. An amuse-bouche is a single bite of food meant to be served at the beginning of a meal, not a plate full of food. Lecter's guests would be better educated.
Other mistake: Looking at a close-up of Ralph Fiennes make-up for his cleft lip/palate, there is a scar from his left lip to his left nostril, but there is a gap in the middle, which should definitely not be there. Once an incision is made, that's it, there is no reason to stop in the middle. In other shots of his face there are no gaps.
Continuity mistake: When Graham and Hannibal are talking for the first time, Hannibal walks right up to the glass wall and there is a close up of his face from Grahams side of the glass. You can see that there is no reflection of Graham on it, thus meaning that there is no glass wall there in between Hannibal and Graham. This happens frequently through out the movie.