(at around 45 mins) Lecter is shown taking a walk in an "exercise cell," with his hands locked behind his back and attached to a cable; he tells Will Graham that he's allowed 30 minutes in there once a week. However, in The Silence of the Lambs (1991), to which this film is a direct prequel, Lecter tells Clarice Starling that he has been in his cell for eight years, and that he knows they will never let him out while he is alive. Although this may seem like a continuity error, Lecter is a skilled manipulator; in the latter scene he's trying to manipulate Clarice into helping him get out of that facility, so it's impossible to discern whether he was telling the truth or not.
(at around 1h 11 mins) When Dolarhyde cuts the bindings on the tabloid, he uses a bolster-lock stiletto with a bayonet blade. In the next shot of the knife in his hand, when he is confronted by the newspaper seller, it's a swinguard lockback (no picklock or liner lock mechanism is visible at the bolster, making it a lockback) stiletto with a standard blade.
Red Dragon ends with Hannibal Lecter being told Clarice is there to speak with him. In The Silence of the Lambs, Hannibal tells Clarice he has been in the cell for 8 years. At the beginning of Red Dragon, Hannibal is caught. Red Dragon doesn't take place over an 8 year period.
(at around 44 mins) Dolarhyde is circling/marking out an image of Freddy Lounds in a clipped article in his journal. In the next shot as he's turning pages, the image is circled but not marked out.
(at around 1h 35 mins) When Dolarhyde is at The Brooklyn Museum, the woman who shows him the painting has eyeglasses hanging on a chain around her neck. After she says, "It's remarkable, isn't it? Two hundred years old... looks so fresh... so vivid" and Dolarhyde leans in for a closer look, she is now wearing the eyeglasses on her face.
(at around 1h 45 mins) When Dolarhyde shoots Ralph, he uses a suppressor (silencer), and the gun makes a light squeak. In reality, gunshots are extremely loud and a suppressor can only reduce their noise somewhat. The gunshot would still have been very loud, loud enough for Reba and the whole street to hear.
Crawford tells Graham that the first murder was Saturday, February 25, and the next was March 28, which he says is just one day short of a lunar month. It's an interval of 31 or 32 days (in 1984, one year 2/25 was a Saturday, there'd be a leap day), which is not even a day shy of a calendar month, let alone a lunar month of 29-30 days. The phases of the moon in the years 1984 and 1989 also don't match well with the dates, providing neither a full moon for lunacy nor a new moon for the cover of darkness the killer is implied to require.
When Dolarhyde's note to Lecter is found Graham asks Crawford if Lecter's mail is opened and Crawford says they can't open his mail without a warrant. Which is not true, all personal mail being sent to a prison inmate, especially in a maximum security facility, is subject to search and inspection, no warrant is needed. The only mail that cannot be opened by prison staff is anything privileged, like a letter from an inmate's attorney or priest.
(at around 45 mins) The character carved in the tree is the Chinese word for "center" or "middle". In the movie, an expert in Asian Studies analyzed it to be a mahjong tile (red dragon), but it is a very common character, even found in the Chinese words for 'China' (literally 'Middle Kingdom'). The mahjong tile that uses this character is called "red center" in Chinese. It is only called 'red dragon' for anglophones as a matter of convenience. To make the leap from 'center' to 'red dragon' is as absurd as someone randomly finding the letter 'A' and concluding it must be the ace of clubs. However, the fact that it is used on its own and it's evidently a calling card of some sort makes it clear that there is more to the symbol than just its straightforward interpretation.
(at around 1h 50 mins) Jack Crawford receives a call to tell him that a body is not who they assumed it was, stating that it has "the wrong DNA". DNA fingerprinting was not invented until 1983, but only the movie's opening takes place in 1980 and the rest "a few years later", even as late as 1989 to lead into The Silence of the Lambs (1991).
Reba McClane is wearing a watch. Yes, she is wearing a Braille watch because she is blind.
(at around 1h 18 mins) The audio tape delivered to the police is clearly a voice-over between two scenes, and the movie never states or implies that the tape got delivered attached to the wheelchair - it wouldn't have survived the fire. The tape is also, of course, edited by Dolarhyde. Why should he reveal his voice to the police if he can edit it out?
(at around 1h 35 mins) When Dolarhyde is at the Brooklyn Museum, the woman who shows him the Red Dragon painting says that it is 200 years old. The painting that he was looking at is called "The Great Red Dragon and the Woman Clothed In Sun" which was painted no later than 1805. Now assuming the movie took place around 1985, that would make the painting around 180 years old, not 200. But people often round large numbers in a context like this where succinctness outweighs precision.
(at around 18 mins) When Will is investigating the first crime scene he walks into a bedroom covered in bright red blood. Since this was several days after the murder, all the blood in the house should be dark brown or black.
(at around 1h 8 mins) When Will is teaching Molly to shoot at the farm, there is no visible recoil when she discharges the revolver. This would be practically impossible with a .357 or .44 in the hands of a novice. There is no flash either, just wisps of smoke. In fact, the gun shakes more while she's cycling the cylinder then when she discharges it. There are also no bullets in any of the chambers. Finally, neither are wearing safety goggles, which as a FBI field agent should be second nature when firing in a range-type setting.
(at around 1h 45 mins) A good part of the living room's floor is doused with five or more gallons of gasoline, but an entire minute goes by before the perpetrator sets a match to it. By then there would have been so much vapor in the air that the whole room would have practically exploded the moment the match was struck.
Actor Ralph Fiennes speaks with an impaired speech, mentioned as due to his character's cleft palate repair, but when we hear "flashbacks" to his childhood through voice-over, the child voice actor portraying his character's younger self speaks without impediment.
(at around 1h 17 mins) When Dolarhyde speaks closely to the captive Lounds, the scar on his upper lip is falling off.
(at around 37 mins) The movie is set in the 1980s, as a prequel to The Silence of the Lambs (1991), but VHS tapes of films such as Mrs. Doubtfire (1993) (1993), Back to the Future (1985) (1985), and E.T. the Extra-Terrestrial (1982) (1982) are seen in a drawer as part of the Leeds family VHS collection. Dating the film from the 1980 opening and "a few years later" after that prologue, and the reference to Saturday, February 25 as two months ago puts it in April 1984 or 1989, the latter more likely as the end of the movie leads directly into The Silence of the Lambs (1991); the 80s tapes may be OK for 1989 but one from 1993 is certainly not.
The Georgia state flag that appears in the movie was the current state flag of Georgia in 2002, but Georgia had a different flag in the 1980s, when the movie takes place.
The title page of the killer's scrapbook is traced from the typeface Arial (recognizable from its distinctive R and G in Red Dragon), which was created in the early 1990s.
(at around 4 mins) The tan leather shoulder holster worn by Will Graham in the opening of the film is a Galco Miami Classic model that was not yet available in 1980 when the scene was supposed to take place.
(at around 1h 40 mins) After Graham finds out the video tapes are what links the victims the aircraft flying at dusk is the outline of a Falcon 2000. The film takes place sometime in the early '80s and the Falcon 2000 was not delivered until March of 1995.
The sound of the copter over the Grahams' house is heard suddenly, out of silence, without any sound in approach preceding.
(at around 48 mins) When Lecter acquires Graham's address, the pulses heard in the handset do not match the ones he is tapping out. When you make a call this way the number of pulses you hear are matching with the tapped ones.
(at around 1h 8 mins) When Molly learns to shoot at the farm, every shot she takes echoes, but Molly and Will are in an open plain. The only way for the shot to echo is if they were in an enclosed space.
(at around 42 mins) When Francis is doing bench presses, a camera operator wearing a black T-shirt is reflected in one of the mirrors.
(at around 1h 18 mins) There is a cord visible when the burning wheelchair is rolling down the street, which is also indicated by a trail of fire left behind it when it has fallen over.
(at around 1h 22 mins) When Lecter is saying, "Clever work on his note, by the way," the camera is reflected in the glass under Lecter's chin.
(at around 3 mins) When the lady at Hannibal's dinner party says, "Hannibal, confess. What is this divine-looking amuse-bouche?" she has a full plate of food in front of her. An amuse-bouche is a bite-sized morsel, or hors d'oeuvre, not enough to fill a plate.
(at around 1h 5 mins) When Lloyd Bowman is in the Library of Congress cracking Lecter's code, he circles the numbers with a red felt tip pen. Highly doubtful that the Library of Congress would allow someone to write in a book.
When we are first allowed to see Dolarhyde's scrapbook (at around 9 mins), various newspaper clippings are surrounded by Dolarhyde's marginalia. On one page of a printed article, the reporter sought to describe Lecter's cannibalism, especially in reference to serving human remains to guests; in that article, the text reads that he cut "mussel" from the bone, a spelling error no respectable newspaper would allow. Later (at around 50 mins), when we see the "Red Dragon" illustration within a book, the blurb on the opposite page tells what museum is archiving it, but refers to the series as illustrations of "Revelations" (the book in the Bible has a singular title), an error a prestigious museum would not let pass. And the first newspaper clipping seen in the title sequence refers to a "sorted mystery" rather than a "sordid" one.
(at around 1h 45 mins) When Dolarhyde points his gun at Reba he calls it a "12-gauge magnum". There are magnum 12-gauge rounds but the gun itself is just called a 12-gauge.
The Leeds family is referred to in the plural as "the Leeds" instead of the proper form "the Leedses".