Continuity mistake: When Bruce Wayne is talking to Alfred while having his arm stitched, in shots from the side he's looking downwards, but in other shots he's looking up towards Alfred. This keeps switching, shot to shot.
Revealing mistake: When Batman's cycle flips the truck that the Joker is driving during the scene in which The Joker is attempting to kidnap Harvey Dent, the viewer can see the geyser of compressed air shooting from the underside of the 18-wheeler's trailer, which is commonly used to flip vehicles for movie stunts.
Continuity mistake: In the scene where Joker is visiting Harvey in the hospital, there is a shot of Harvey's face just before Joker takes his hand, and there is a tear on Harvey's cheek. However, in the next shot of Harvey's face, the tear is gone, and there is no trail where the tear would have fallen, and Harvey's hands don't go to his face.
Continuity mistake: When Dent is talking in the hospital after being rescued, the pillow is bloody on his left side (where he was burned) then the pillow is clean again in another shot.
Continuity mistake: In one of the first scenes with Det. Ramirez, you see her holding a cup of coffee. She switches between holding the cup with two hands, then one hand and finally two hands again. The cuts in the scene are immediate and linear, so she could not have changed how she holds the cup in between cuts.
Revealing mistake: During the interrogation scene, when Gordon first enters, as he begins to close the door if you look in the glass reflection on Gordon's left (screen right), you can see the door open again slightly after he shuts it. In the next shot, its completely shut and locked.
Continuity mistake: When Batman is about to glide into Lau's building they show him standing on the ledge about two meters from the corner, ready to make his jump. Cut camera angle to an overhead shot and he is standing on the corner of the building when he makes his jump.
Revealing mistake: In the scene where Batman is taking down the SWAT members to prevent them from harming the wrong people, one of the SWAT guys is lying on the ground and attempts to stand up. The clip for his gun contacts the ground and flexes like a rubber stunt gun would, not a real clip and gun.
Factual error: As Two-Face, Harvey Dent is missing his left cheek and all of his left lips, yet he is able to talk without any severe speech impediment. Not possible; although people with similar afflictions are able to talk, there is a discernible difference in not only the words they speak, but how the words are formed. Speaking words with the letters "P" or "B" require either a closed mouth or pressing the tongue against the upper lip. Two-face was unable to do either, yet speaks perfectly.
Factual error: When Batman jumped and landed on top of the van driven by Scarecrow, the van stopped dead in its tracks. The forward momentum of the van would have kept it moving, even if it were undrivable. The van stopped at the precise moment Batman landed on it, so Scarecrow didn't have time to slam on the brakes.
Factual error: Batman jumps from Hong Kong's IFC (International Finance Centre) Tower 2 to IFC Tower 1 (where Lau's office is located). But when you see the lobby of the building (IFC 1) where Lucius Fox left his phone, it's actually the lobby of another building in Central Hong Kong. That building is The Center. Also, I'm not sure where Nolan shot the meeting between Fox and Lau, but it was definitely not IFC 1 as we can see the Hong Kong Four Seasons hotel in the background, and that building is next to IFC 1, not across from it.
Continuity mistake: In the scene when the Joker talks to Harvey in the hospital, Dent's head changes position from the left side of the pillow to the right.
Continuity mistake: When Batman is removing the part of the wall with the bullet in it, we see the bullet hole is off-center, to the left side of the block that Batman carves out. In the next scene where we see the mounted gun shooting specialized bullets into blocks, Bruce compares the block he removed from the apartment, which is in a plastic bag, to the holes left in the sample blocks. The hole in the block from the apartment is now in the center of the block, not on the left side as it was when he removed it.
Plot hole: The Nomex survival suit that Bruce gets from Lucius Fox in Batman Begins is bulletproof, knife proof, and can stop anything but a straight-shot, per Fox. All Bruce did was spray paint over it to make the batsuit. But in the beginning of The Dark Knight, Batman gets mauled by a dog which chews through the suit and cuts Bruce's arm, causing him to need stitches.
Suggested correction: The suit still has seams, through which the dogs can bite.
The suit he was wearing is knife proof, meaning there's aren't suppose to be any "seams" for a dog to bite through. It was the later suit he requested that would be vulnerable to knife attacks.
Lucius told Bruce in Batman Begins that it would stop a knife, he didn't say it was knife proof. This was likely in reference to protecting vital organs from stab attacks, etc, not the weakest areas in his armor from dog bites. There was always going to be flexibility, protection, and weight consideration trade-offs for optimization purposes with any armor he wore, not just his 2nd.
Continuity mistake: When the Joker first opens fire on the prison van, you can see that his pistol locks open as if it were empty. However, if you look closely, you can see the empty shell is stuck between the slide and the chamber. In the next shot, he keeps on firing like nothing ever happened.
Factual error: Despite the stunt looking really cool, the flipping of the tractor trailer simply would not have occurred as shown. Assuming Batman does exactly what we see regarding the cable, the truck would have just torn the cable out of the asphalt along with the lamp posts, barely being slowed by them. Ignoring this, if the cable's anchor held firm, the cable would more likely break. Failing that, the truck would simply, abruptly stop. But in no case is it capable of generating the force required to make the trailer rise up and turn with the entire rig over its own front end. Further, the tractor and trailer are not a single, rigid piece as shown. The two pieces would form a "V" while in the flip due to the trailer lagging behind the tractor as it rotates over. Once bent, the hitch would fail and the trailer would drop back on its wheels.
Continuity mistake: When Batman throws the Joker over himself and off of the building he catches him with his rope gun, in the first shot two cables are shown holding him up and in the next there is only one.
Continuity mistake: In the interrogation scene just before Batman slams the Joker's head into the table, it can be observed that the Joker's nails are somewhat long. However, as the scene escalates to where the Joker's back is against the wall and he's clutching Batman's forearms, the Joker's nails are short.
Continuity mistake: In the scene where Batman is interrogating the Joker at the police station, Jokers make-up smears and is rubbed off when he rubs his forehead (after Batman slammed it into the table). Batman later in the same scene strikes the Joker in the face. He should have some make-up on his gloves left, yet does not.
Continuity mistake: When the Joker is about to burn his half of the money he walks up to the Chechen and says something and then in the very next shot the Joker walks up to him again.
