After Gerry gets smacked in the face by the 'broken' suspender clasp, we see the silver clasp land under the dresser. Yet, when he's moaning and lifting his leg to get onto the bed, we can actually see the clasp still intact on the front suspender that came loose, which is dangling right behind him (just look between his legs). Of course, in the next shot, that clasp is gone. Since the silver clasp is one of the plot points, this is bizarre to say the least.
When Sam is in his bedroom, after he finds the Cube sliver it falls and dramatically burns a hole through the bedroom floor, making its way through the kitchen ceiling, and when it lands on the table it transforms the kitchen appliances. This is quite impossible since Sam's bedroom is in fact over the living room (there is nothing on the ground floor below Sam's elevated bathroom, and in the first movie Jazz hides in this open space as Ron mentions a blown transformer), and the kitchen is actually located between the den and dining room, at the other end of the house. The house has both a den and a living room - the couch in the den faces a flat screen TV on the wall, and the couch in the living room faces the fireplace with paintings on the mantle. If they were to follow the actual floor plan of the house, the Cube sliver would have landed in the area of the piano in the living room, but where would the fun have been in that?
There are two scenes during which Harry is shown having visions of the Dept of Mysteries while he is asleep. The first scene occurs after Harry's confrontation with Seamus in the Gryffindor common room. There are shots of Harry lying in bed wearing a short sleeve, crew neck tee shirt, but when he is startled awake by the vision of Voldemort, he sits up wearing a buttoned henley tee. The next day is the first day of Defence Against the Dark Arts class with Umbridge. That last shot of Harry in the henley tee shirt was cut from a later scene. Later in the film, when Harry has the vision of Arthur Weasley's attack, he is wearing the henley tee shirt.
In the end, when the President is visited by the X-Men, he receives a blue binder, which is laid in front of him on the table. When they have left, you see a shot including the President's desk, and you can see that the only thing he has on the table are some sheets of paper, stapled in the upper left corner, opened up. Then the shot changes to a close-up of the President, and then back again, and you see the blue binder in front of him, closed, and the papers have disappeared.
Merry and Pippin were bound when taken by the Uruk-hai, and the bonds weren't cut until after they managed to escape during the fight. Yet, when the horse almost crashed down on Pippin, he had his arms spread out up near his face, not bound, even though they weren't cut until later. In the next shot, his hands are bound again.
During the championship game, one of the final shots shows Scott's dad coming out of the crowd to congratulate him. There is a fan behind him who stands up to cheer and deliberately exposes himself to the camera.
During the fight scene with Sandman in the armor car, the Terminal Tower can be seen in the background, which is a landmark in Cleveland, Ohio (where the scene was shot), not in New York city.
The movie is supposed to take place in and around New York City, however during the car chase where Angelina and Brad are fighting off the three BMW's, a wide shot clearly shows a street sign announcing Los Angeles.
On Utapau, when Obi-Wan faces off with Grievous, Grievous sends 4 magna guards at Obi-Wan. Obi-Wan force-pulls something from the ceiling to crush the droids. But in the ensuing fight between Obi-Wan and Grievous afterward, the ceiling thing and crushed droids are gone.
When the seven dwarves run scared down the stairs and out of the door, Dopey pulls the handle of the door from the inside until it breaks out and falls away. The next scene when the dwarf opens the door, the handle is there again.
While Indy and Marion are in the Well of Souls, and they encounter the snakes, Indy falls to the ground only to be confronted by a hissing Cobra rearing its head. Look carefully and you'll see the snake's reflection on the safety glass between it and Indy. Briefly you can also see the torch's reflection while he's waving it around. [This has been corrected in the new DVD set. You can only see it if you have the original VHS. I think it's visible in the "making of" on the DVD as well.]
In his cameo in this film, Tim Burton is holding something in his left hand that looks like a remote of some sort when we first see him in the background. Then the shot changes to Debbie and back to Tim, but this time he doesn't have it. Then the shot changes to Debbie again and then back to Tim, and he reaches to his far right and picks it up.
In the scene towards the end of the film where Tarzan is having a fight to the death with Slade, Tarzan manages to put the wire noose around Slade's neck. Next shot you see is Slade losing his balance at the edge of the cliff and about to fall. The noose somehow comes off Slade's neck and is discarded by Tarzan (to the right side): it falls on the cliff and appears to stay there. The next shot, Slade falls to his death and his body is on a rock below. Mysteriously the pole with the noose falls out of Slade's hand into the water. This scene is on Youtube - Tarzan's Greatest Adventure Pt 2.
When Ace and Melissa are in bed together having sex if you look close enough you can see that she is wearing underwear.
In the 'Gaston' song sequence, near the end, Gaston is sitting in his huge antler chair with Lefou. In the wide shot, there is a bear rug behind the chair. The camera does a close up of Gaston, then in the next wide shot, the chair is on top of the bear rug. Also, after this, Gaston gets up off of the chair and in the next shot, both the chair and the rug disappear completely.
The "video history" of the crashed USAF ship makes it very clear that the planet is uninhabited when they "landed". I can understand how a race of apes develops - they had a bunch of them on board. I can understand how a race of humans develops - they are descendants of the original crew. What I don't understand is... where the heck did all the horses come from?