Revealing mistake: When Hallie trashes Annie's cabin and the huge water balloon is about to fall on Annie's head, the camera is at a downward view and Annie clearly steps into the trail of the balloon instead of jumping away. (00:18:05)
Revealing mistake: Just before Marguerite tastes the chocolate Henry gives her, in the shot of the group walking past a pen of geese, the modern, flat, white soled shoes (likely canvas sneakers) the sisters are wearing are visible as they walk. (00:51:00)
Revealing mistake: When they are all in the camper van Tiffany gives Chucky a biscuit then walks away from him, from the way she gave him the plate, they would have all fallen off. (01:07:35)
Revealing mistake: In the scene where Captain Love and Antonio Banderas (as Zorro) meet in the hallway of the hacienda, two guards rush down the hallway and drop their rifles and swords. Zorro asks them to bend over and then proceed to kick/nudge them out the window. If you watch carefully, you'll notice that the guard on the right (furthest from Zorro) reacts to the kick too early. (01:33:30)
Revealing mistake: In the New York meteor shower scene, most of the cars blow up without having been hit at all.
Revealing mistake: There are several scenes Meg Ryan and Tom Hanks' computers do not have any telephone wires attached to them. They are in an era where they were using AOL dial up, as heard by the connection. They were not using wireless.
Revealing mistake: When Mary of Guise is found dead by her nephew, he lies her down and puts his head on her chest. As he comes down, her eyes slap shut! If she were dead, they would remain open.
Revealing mistake: When Angus is chasing his Mum, Sally, and Dorian in the helicopter you can see through the windsheild of the helicopter that the road is blocked off with orange cones and police cones when earlier there was traffic on the road.
Revealing mistake: When Sandra Bullock and Nicole Kidman drag her sister's "dead" husband/fiancé into a room, the door hits him on the head and his eyes move.
Revealing mistake: When Shakespeare is getting dressed and talking with Viola in the bedroom, you get a quick glimpse of Joseph Fiennes' modern day men's briefs under his tunic.
Revealing mistake: When Puffy the dog bites Ted and pulls him along, Ted digs his fingernails into the floor, they scrape along, making marks. If you look very closely you can see faint pre-made marks made in the floor, where he drags his nails along. (01:28:45)
Revealing mistake: When Finn draws a fish at the beginning of the film you see a dent already in the paper at the spot where he draws the eye. (00:03:10)
Revealing mistake: You can tell all shots in the parallel world where there is writing visible are simply regular shots being reversed because Molly Ringwald's watch and ring, which she wears on her left arm and hand, suddenly are on her right arm and hand. Especially obvious in the scene where she goes over work papers with Sandy.
Revealing mistake: When Steve and Julia talk in the garden on New Year's Eve, there is plenty of snow but no other signs of cold temperature, like breath clouds. (01:21:05)
Revealing mistake: At the end a character is killed and you see him lying on the floor, dead, but still breathing.... (01:43:00)
Revealing mistake: One of the very last clips of the movie - one showing the barricade with a lot of flags - runs backwards. You can tell from the way the flags wave.
Revealing mistake: The de Havilland Beaver takes off the first time for Makatea King Kong peak is in the background (a known peak on Kauai). When they land on Makatea there in the background is King Kong again, right where they took off from.