Continuity mistake: When Kenny is brought into the hospital, there is a schedule on the wall next to the door (Dr. No is scheduled to 'Kill Bond'). When Kyle is worried that their Mums will find out that they went to the movie, the Doctor column has vanished from the chart. A little later, the columns are reversed.
Continuity mistake: The first time the South Park boys see the Terrance and Philip movie, their order in their movie theater seats is (from left) Kyle, Stan, Eric, and Kenny. After a couple leave, saying "Well, what do you expect, they're Canadian", a shot from behind shows that Stan and Eric have switched places. In other shots they're in the original positions.
Continuity mistake: During the "La Resistance" song, Gregory is singing with the other kids in on group and Cartman, Stan and Kyle are singing in another group. However, as it shows the kids, Satan, the mothers against Canada and the fathers, Cartman, Stan and Kyle and the other kids are all together. They couldn't have been in the group with the other kids the whole time because another kid has appeared next to them.
Continuity mistake: In the cinema hall, when we see the South Park kids before the movie starts, you can see what looks like a baby, who we can presume is Kyle's baby brother, sitting next to him to his right. However, at the part in 'Asses Of Fire' where Terrence and Philip are having a farting competition with a traffic police and after a couple left the cinema in disgust, the camera cuts back to the gang but the baby has disappeared. After the gang leaves the cinema 3 hours later, the baby reappears and is seen dangling on Kyle's arm.