Continuity mistake: In Chapter 19, Wade describes the small efficiency apartment he has moved into, which used to be an average hotel room. He says at one point that the room "was basically a cube, about ten meters long on each side." A ten-meter cube is actually a really big room - that's over 32 feet on each side, including ceiling height. Then, just to confirm that this is indeed a mistake, later in the same chapter he refers to "my tiny one-room apartment."
Factual error: In the book Teabing is a die hard British patriot, yet he refers to the sport of soccer. NO Englishman would use the word soccer for the game of football. [People keep trying to correct this - you've really got to accept it. It's nothing to do with Teabing being older - soccer may have been used in the very early days of the game, but the governing body of the sport in the UK is the Football Association, formed in 1863, demonstrating how that was the accepted word for the sport even then (otherwise it would be the Soccer Association). Likewise the international governing body, FIFA (Fédération Internationale de Football Association), formed in 1904 - no mention of the word soccer there either. And it won't be him changing it for Langdon's benefit, considering a) Langdon's intelligent enough to know what he means, and b) he's so determinedly English about everything else. This site is run by a Brit, and it's not getting changed. :-)]
Continuity mistake: Dumbledore tells Harry at the end that Lord Voldemort is the last remaining ancestor of Salazar Slytherin. But ancestors are in the past - he means Voldemort is the last descendant of Salazar Slytherin. Not a mistake Dumbledore would have made. (Corrected in later printings.)
Continuity mistake: Before Harry and Hermione go back in time, it mentions that Buckbeak is tied to a tree. But when they go back in time, Buckbeak is tied to a fence.
Continuity mistake: During Priori Incantatem, Voldemort's victims come out in reverse order. However, James comes out before Lily. He should come out last, because he was killed before Lily. (Corrected in later versions of the book).
Continuity mistake: Harry buys the book "One Thousand Magical Herbs and Fungi", but later, the title changes to "One Hundred Magical Herbs and Fungi".
Continuity mistake: How can Ron and Lavender be in a 'prominent corner' of the Common Room when in Harry Potter and the Philosopher's Stone, it says it is a circular room?
Factual error: In Chapter 5, Koontz explains how Grandma Rowena started smacking her lips while eating, at the age of 75. He then says this same event happened "halfway between her seventh and eighth decades". But at 75, she is actually halfway between her eighth and ninth decades (or, if you prefer, halfway through her eighth decade) - much like the 1700s are the 18th century, not the 17th.
Factual error: In chapter 21 Vittoria states that "everything has an opposite. Protons have electrons." Protons and electrons are NOT opposites. The opposite of a proton is an antiproton, the opposite of an electron an antielectron (or positron). Other than having opposite charges, a proton is completely different from an electron, ie. a proton is a hadron made from 3 quarks, Up Up Down, making it a baryon. An electron is a first generation lepton and is a fundamental particle. As a physicist, Vittoria wouldn't make this mistake.
Factual error: When Arnie and Leigh gives the hitchhiker a ride, on page 265 (Chapter 34), it says that the hitchhiker opened Christine's rear door. But Plymouth Furies of that era had only two doors.
Continuity mistake: Eddie's broken arm changes around, sometimes it's the left arm that's broken, sometimes it's the right.
Continuity mistake: The pickup truck with the painting of the Gypsy woman and the unicorn in Chapter 6 changes into a VW microbus in Chapter 18.
Continuity mistake: At the beginning of the book Meggie mourns leaving the farmhouse she has lived in for just under a year, but at the end of the book she suddenly remembers having lived there for the past several years.
Plot hole: When Julius is going after Pompey to Asia Minor and he reaches the harbor in Greece he tries to talk to the sailors but they don't speak Latin. So he asks Adán to translate for him, but he is unable to since he hasn't learned Greek yet. But Julius is fluent in Greek himself, he was taught as a boy and uses the language on several occasions throughout the series, including in this book. Why couldn't he just talk to the sailors in Greek himself?
Continuity mistake: In the chapter entitled Smooth Criminal, Reed is asked by the Billing's Girls to steal a physics test and that she has 15 minutes to do it. Early in the chapter she states that after glancing at her watch she had already wasted 4 minutes but at the end of the chapter she states that she wished she'd had time to put on a watch as she had no idea how much time was elapsing.
Continuity mistake: Greg says that Hero Points are printed on sheets of 10 (page 52), but on the next page, Erick is holding a sheet of 12 Hero Points. On the page after that, the Hero Points are back to a sheet of 10.
Continuity mistake: When Aladdin is battling Jafar, he is shown holding a sword. On the first page of this, the part of the hand guard on the sword that is on the sharp side of the sword is curled up and the back side is curled down. But the next page with the sword shows this reversed.
Factual error: Petra is reading some details about the size of a murder weapon used to commit 6 similar murders. The diameter of the weapon is estimated at 77 centimeters. It says according to Petra's ruler, 77 centimeters is 3 inches. This should be 77 millimeters as 77 centimeters is about 30 inches.
Continuity mistake: When Clay and Tom are threatening to break into the hotel, Tom says "I'm going to grab a kerbstone and smash the glass", but Clay says "A curbstone?" Since they both say it, there should be no spelling error.
Plot hole: When the time stop is almost over, Root uses his "finger" to render Cudgeon unconscious. However, later in the book it is explained that if you lose your consciousness during the time stop you would immediately jump to the end. Cudgeon should have disappeared, and Foaly (or someone else) should have realized how Artemis planned to escape.