Continuity mistake: Rumpelstiltskin looks completely different in this movie than he did in the previous film Shrek The Third; Prince Charming momentarily talks to Rumpelstiltskin in the tavern during the third film, and the character looks completely different, has a different voice and different demeanor.
Plot hole: Had one or more locomotives coupled onto the real runaway's front engine, or even just been pushed by it, anyone aboard the "rescue" engine could have just walked to the unoccupied ones and shut them down - no copters or fireballs required.
Continuity mistake: During Andy's daydream at the beginning of the film, Mr. Potato Head has an eye patch over his left eye. When the daydream cuts back to reality we see that Andy has removed Mr. Potato Head's left eye to symbolize the eye patch. But when Andy's mum comes in with the video camera, his left eye is suddenly back in. (00:01:15 - 00:05:25)
Plot hole: In the end, all they have to do is ask the President, when he's conscious (Liev didn't kill him; he just knocked him unconscious), who killed everyone in the control room and nearly killed him. He would know who the traitor is and it's not Salt - when they look back at the facts, they'll see how Salt only killed when she absolutely had to, and how she saved lives and stopped a 3rd world war.
Revealing mistake: In the last scene where Edward and Bella are sitting in the sunny field, Edward is not sparkling. (01:52:55)
Revealing mistake: When Leo is laying his dead kids on the grass, the little girl keeps moving her eyes and breathing.
Continuity mistake: Right after Bennett takes off in the plane, Claire throws a gun to Alice. Between the slow-motion shots, the gun switches position in mid-air before Alice catches it. In the shot of Claire throwing it, the barrel is facing to the right, meaning that it should be facing to the left in the shot of Alice catching it. But it still faces the right when she does. (00:58:30)
Continuity mistake: When Xenophilius draws the Deathly Hallows symbol, he draws it so that the bottom of the line touches the bottom of the circle. The shot cuts away and back again when he draws the triangle, but the line is no longer touching the bottom of the circle. (01:49:40)
Continuity mistake: After being chased by soldiers after talking to his uncle, Dastan gets into a swordfight with Garsiv. As soon as it starts, Garsiv hits a pillar with his weapon knocking a significantly large chunk and a another smaller chunk out of it. In the immediate shot, the size and locations of the two chunks differ.
Factual error: On the cliff top before the battle on the beach, you are treated to a lovely if fleeting glimpse of wind farm turbines, not really fitting for the 12th Century.
Factual error: When Mark types email addresses in to tell people about facemash, he writes to several people @harvard.edu. At the time the movie takes place, undergraduate email addresses were all of the form firstname.lastname@example.org. Furthermore, the network brought down by facemash would have been referred to as the FAS network. (FAS stands for Faculty of Arts and Sciences; the eponymous network covered all buildings within the College and Graduate School of Arts and Sciences.).
Continuity mistake: Gamble and Hoitz get thrown to the ground when the accounting office explodes. In an overhead shot of them rolling around on the ground, Gamble's wooden gun has fallen from its holster and is lying on the ground. Cut to a side shot and the gun is back in its holster. Gamble had both hands covering his ears the whole time, he did not pick up the gun. Then comes another overhead shot, the wooden gun is again missing from the holster. (00:48:45)