Continuity mistake: When Lenny and Oscar witness Soto's death, they are standing next to each other. But, in the next shot where Manny looks at them, Oscar is standing further apart from Lenny. They stand next to each other in the next shot, but in the shot where they flee, they're standing apart from each other again.Bradley Bing
Continuity mistake: When Sid is relaxing in the 'goo' and has it splattered on his face (no-one knows what it is), he wipes his face off with Manny's trunk, none disappearing. In the next shot, the 'goo' has completely disappeared from Sid and the baby.