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...
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)
Suggested correction: Both the text in the film and the corrected text are technically correct. It's not a mistake.
The text in the film is grammatically incorrect. "Muore" is singular and would not be used for 130 people. Also, accident in Italian is incidente. Third, even if it were to be accidente, it would be "accidente di aeroplano." The text in the movie is reversed.
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.
Suggested correction: The scars could easily have come from something else. His skin is not impervious to damage, so extreme trauma would break his skin and leave a scar.
David's skin is impervious to damage. After waking up in the hospital after the train crash, Dr. Duban tells David that not only does he not have any broken bones, but also that he doesn't have a single scratch on him. If his skin wasn't impervious, then he should have suffered major cuts and lacerations from the wreck. Even during the flashback of the accident when he and Audrey were teenagers, Audrey is show bruised and bloody while David is completely unharmed.
Suggested correction: David is not "immune" to disease. He has a much higher resistance to disease.
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.
Suggested correction: The 'unbreakableness' of Bruce Willis' character is that his bones cannot break. (According to the explanation given by S. Jackson's character) His skin can be punctured and so forth. If every part of him was invulnerable he couldn't shave or do many bodily processes.
His unbreakableness does extend to his skin. This is first seen in the hospital when David wakes up in the hospital and the doctor tells him he doesn't have a scratch on him. The second time is during the flashback scene of a teenage Audrey and David both ending up in an automobile accident and Audrey being shown bruised, scratched and bleeding and David completely unharmed.
Suggested correction: According to a previous explanation, David's "unbreakableness" is limited to his bone structure and general health. His skin can break and heal naturally. See the correction on why the scar from his ear piercing shows.
Twotall
When David wakes up in the hospital, Dr. Dugan tells David that he doesn't have a scratch on him. If his unbreakableness was limited only to his bone structure, he should have woken up covered in scratches from not only the force of the collision but also from the glass as he was sitting next to the window.