(at around 16 mins) When Victor is in the woods saying his vows, he puts his ring on the "branch"; a.k.a. the corpse bride's hand, and he puts the ring on the pointer finger. However, in the next shot when she says "You may kiss the bride," the ring has magically moved to her ring finger.
(at around 1h) During the dinner scene, as the camera pans up and down the table, we can see that everyone (including Mr. and Mrs. Everglot) have some sort of chicken-like bird on their plate. However, when the "guests" arrive, Mr. and Mrs. Everglot's chicken turns into soup.
(at around 28 mins) When we are first introduced to "Scraps", he is in a wrapped gift box. When Victor drops the box on the ground and Scraps appears, the box soon disappears.
(at around 4 mins) During "According to Plan" when Maudelaine Everglot opens the safe, you see she is wearing a gold wedding ring. However, when she closes it, the ring is gone. It reappears later. The same thing happens to Nell Van Dort. In one shot she has her ring on but in the next it's gone.
(at around 10 mins) When Victor is first talking to Victoria, he's fiddling with his tie. In one shot it is out of his jacket and wrinkled but the next time he's shown, the tie is tucked in and there isn't a wrinkle in sight.
(at around 58 mins) During the Wedding Song, a baker's nose gets knocked off and mixed into the wedding cake batter. Towards the end of the song, while they're carrying the cake through the street, his nose is back with no signs of damage.
In fact, right after nose is dropped into the batter, the woman baker takes the nose out of the batter with a spoon.
When Victor is rehearsing his vows in the forest, he puts the ring on the "branch" which turn out to be Emily's hand, and he places the ring on the index finger. When Emily grabs his had and pulls him down and then comes up again, the ring is now on her ring finger.
(at around 7 mins) When Victor first plays the piano, the arpeggio he plays is actually a C fully diminished (C-Eb-Gb-A-C). The arpeggio that sounds is C Major (C-E-G-C).
(at around 22 mins) During the Skeleton Dance, a trombone is being played. But the sound is of at least two muted trumpets.
In all the scenes with a piano, the keys that are played don't sound out the right melody. For example: Victor plays Middle C, but the sound that comes out is not Middle C, but D, sharps and flats are heard coming from white keys instead of black keys, etc.
(at around 51 mins) When Victor and the Bride are playing their piano duet in the underworld, the notes the Bride's fingers had been playing continue to repeat as her hand breaks off and climbs up Victor's arm.
When Victor practices his vows in the woods, there is no priest present to legalize the vows. Furthermore, only the Corpse Bride says "I do", whereas Victor never does.
Emily is shown having a 'sock' on her skeletal left leg, while the right leg is made of flesh, does not have a 'sock' on it, whether its a sock, flesh or just a design flaw is not made clear.