Continuity mistake: At the dinner party, when Danny continuously puts butter on Lacey's side plate, in the closeup Lacey's right arm is on the table, but in the following shot she is now holding a glass with just her elbow on the table. (00:29:00)
Continuity mistake: In the scene when Robert De Niro asks Joe Pesci to punch him, you can see blood on De Niro's face at one point. Then you in the next shot of De Niro, there is no blood on his face.
Continuity mistake: When Boris Amphibiensky fails his high jump attempt during track and field, one of the bar's ends sticks to the post while the other reaches down to the ground. But the bar's length is only about an eighth of the posts' height, which is more than 77 feet, so the one end shouldn't reach the ground while the other still hangs on to the post's top.
Continuity mistake: Rosa bit Tommy on the right corner of her bottom lip, but when she wipes blood away it's from the left corner of her bottom lip.