Character mistake: In the final scene, one of the newspaper clippings on the killer's office wall reads something like, "Huge Mudslide in Mexico: All Killed Expect Newborn." The penultimate word should be "except." (01:35:55)
Factual error: When Elijah first meets David at the gallery, he says that he has Osteogenesis Imperfecta Type 1, which is the mildest form of the disease. But Elijah then states that there are types 2, 3 and 4, and that type 4's don't last very long. The types are not in order of severity, type 2 is the most severe form. Type 4 is actually one step more severe than type 1. (00:30:05)
Continuity mistake: After Willis rescues the people, he's at breakfast with his son and wife. He slides the newspaper to his son. Close-up on paper (beside orange juice) shows "Bold" typestyle on story slug. Camera pans up to Willis, cuts to son, cut back to newspaper. Suddenly typestyle is italicised (noticeable on "f" in "found"). (01:34:30)
Continuity mistake: In the scene where David is looking through the newspaper clippings, he flips through them, and if you watch carefully, you will see one of them appear twice. (00:33:30)
Continuity mistake: In the final scene of Samuel L. Jackson's office when we first see Jackson wheel himself down the last ramp towards his desk, three computer towers sit below the desk - two off to the left side, one off to the right with space between to wheel his chair up underneath. After the scene cuts to Bruce Willis and then back to Jackson, the two towers on the left have been moved closer to the one on the right. (01:34:10)
Other mistake: Bruce Willis's character has a very clear scar on his forehead in some scenes (I think it's on the right as you look at him) - doesn't really fit the whole "unbreakable" theory. You'd think they could have put some makeup on it...
Continuity mistake: After David returns from the hospital he pauses at the bottom of the stairs. First his watch is visible then in the next shot it's covered by his sleeve only to be exposed again in the next shot.
Continuity mistake: The train derailed "just before" (according to the news) 3:20 pm, as seen in the scene where Joseph watches the news on TV (clock over the TV). But when David reads the newspaper later when lying in bed with Joseph the newspaper says it derailed at 9:34 am. Seen on DVD (European Version) (00:08:20 - 00:31:10)
Continuity mistake: In the scene where Bruce Willis is sitting at the table with his wife and son, there is an orange juice container on the table, the type of container that is a carton but has a screw on cap on the top. When Bruce's son is about to sit down at the table, the cap on the OJ carton is facing Bruce. When the camera focuses on the child, the cap is facing the boy, and no-one had touched the carton. (01:29:40)
Visible crew/equipment: When David gets off the Bus to see his son playing football the boom mic is visible. Look closely to the far left of the screen in the reflection of the bus window and you'll see the large stick like mic briefly.
Character mistake: Various newspaper clippings are shown on the wall. There is one apparently in Italian saying "130 muore en aeroplano accidente." If this were Italian it would read: "130 muoiono in un incidente aereo." If instead it is Spanish it should read "130 mueren en accidente aereo." (01:40:00)
Other mistake: David is supposed to be immune to disease, which is why no one can ever remember him getting sick, but at a number of points in the movie the Chicken Pox scars on Bruce Willis's face are visible. If he was immune to disease, he should never have had Chicken Pox. I noticed this best in the scene where he asks his wife if she can remember him getting sick, look at his right temple.
Revealing mistake: When Bruce Willis bumps the guy in the stadium with the gun in his pants he has one of his "flashes" and the camera zooms in in slow motion to the side of his face. You can see that his ear is pierced. He must be "breakable" if he has a hole in him.
Continuity mistake: When Mr. Glass is at the comic store, he hits 2 or 3 comic stands. From the last one, 7-8 comic books fall down to the floor but in the wide shot over 20 are on the ground.