Continuity mistake: The overall timeline of the film is about twelve months but it is inconsistent as far as the seasons. When Blomkvist arrives at the Vanger's island, it is the dead of winter with deep snowfall. A short while later, when Blomkvist is talking to the detective on a pay phone (who asks if he is surviving the winter weather), the snow is gone and the deciduous trees have no leaves, but a few minutes later, when the scene cuts to Henrik Vanger being rushed to the hospital, it is suddenly the middle of summer, sunny and the trees are in full bloom. When Lisbeth arrives on the island, and she and Blomkvist are sitting outside at night talking, the trees close to the house are bare and a howling wind can be heard in the background, but the next day trees have leaves. Some weeks later, when Lisbeth saves Bloomkvist from Martin, it is winter again, with heavy frost on the ground and trees are bare once more. A little while after that, when Lisbeth and Blomkvist go to find Harriet, trees on the street are in full bloom. A day or two later, when Blomkvist is talking to Harriet in the park, it is apparently now early spring because the smaller deciduous trees are only just beginning to sprout new leaves while some bigger ones have none at all. At the very end, it's just before Christmas again.
Other mistake: When Gil is walking by the banks of the river, watch the left side of the bridge ahead and you'll see a crowd watching the filming.
Continuity mistake: Kiefer Sutherland throws the suitcases a few steps in front of the middle of the stairs of the entrance of the house but when someone else picks them up, they are on a side of the stairs and close to them. (00:32:45 - 00:33:40)
Factual error: Near the end of the movie, when they go to steal the boat, there is a Puerto Rican flag in the front of the boat. This flag has the royal blue triangle, instead of the light blue that would have been in the 1960's such as all the other big flags used on poles.
Audio problem: When Rochefort yells "Finish them off!" during the attempted ambush of the Musketeers, the sound doesn't match his mouth.
Continuity mistake: When Ren is dancing at the drive in, he starts dancing with a girl then stops to watch her. When he starts dancing again he moves slightly in front of her in the shot. Then in the next shot they are side by side.
Continuity mistake: The red spill on Mavis' blouse changes size in different shots.
Continuity mistake: At the airport Tim gets a red Chevy Cobalt for a rental car. It's a base model with no rear spoiler. Later he is seen driving a red Cobalt with a rear spoiler.
Continuity mistake: When Felipe is telling Jill that he loves her, the level of their heads changes every shot.
Continuity mistake: The giant maker compound was purple when Franqcuer was created, but it turned orange when Lucille made another giant flea.
Factual error: In the scene where Jack Black is kneeling over Shirley MacLaine's body in the garage, you can see the outline of his smart phone in his pocket.
Continuity mistake: When Valerie's father was the werewolf, his right paw was burnt. Then, when we see the hand later, there isn't a scratch on it, but again later, we see that it is, once again, looking burnt.
Factual error: The movie takes place in Stamford Connecticut (per locations and is shown on cop cars). Eva buys a bottle of wine in a supermarket, but in CT only beer can be purchased in a supermarket. (00:25:15)
Revealing mistake: When the final round starts and Rickshaw's broadcast ends, the usual countdown numbers appear on the screen. In this shot the camera is panning to the left, and you can see the numbers sliding around a little as they change. This makes it obvious they are superimposed on the film, and not actually on the TV. (01:01:20)
Factual error: In the climax of the movie, Nicholas Cage uses a nail gun like a marksman, hitting with precision the bad guy that holds his wife tight. Besides this skill of his coming out of left field, a nail gun does needs a surface against the opening. It does not shoot nails in the air without pressure being applied, it's a Hollywood trope. (01:18:45)
Other mistake: In the scene where they are all running down the stairs of the tower and going into their houses to get their weapons, Moses goes to the lowest floor of them all. Near the end of the film Moses tells Sam to go one floor down to go to his flat which can't be right as he went several floors down to his flat earlier.
Continuity mistake: When Justin gets a text from Mike's cell phone, it shows a close up of the screen. In the "to" box, it says Nikki although it's Mike's phone.
Visible crew/equipment: When Bernice tells Josh and Rachel to go with Alice so she can talk to Lisa and Stanley, the two red tape marks can be seen on the floor, under the table. (01:29:20)
Continuity mistake: The amount of damage on the guys' car decreases between shots during the race.
Continuity mistake: When Marcus Aquila and Esca set off for the North they are riding horses, Marcus on a dark brown horse, with a short mane and Esca on a bay (you see close ups of them on the horses, and several screen shots of them galloping on them). However, after their first overnight stay in the North, Marcus' Horse is black with a long mane, Esca's bay horse is suddenly a white horse with no explanation for this. His horse remains white for the rest of the movie.