The video trainer says, "Welcome to tape 7 of the bus driver's video guidebook," though it is actually tape #35 that Ms. Crabtree pulls out.
Kenny is looking out of the school bus window several times after he was dragged away by the monster.
When Gerald sings, Kyle puts his hands up to his face in embarrassment, but his gloves are off. Before and after, though, his gloves are on.
When the kids land in the ice cream bucket, they end up in their original seats, and Kenny is present once again. So is Cartman's cake tin. Also, although the bus has been split in two, the floor shows continuity from front to back, as if it had not been split at all.
When Kyle looks out the back window, a reflection of the dark canyon below can be seen on the window. But the bus was in no position to make that reflection possible. If it were, it would be falling.
When Clyde and the red-haired girl finally stabilize the bus, they are running back to the front, but the seats are facing down, implying that the front of the bus was facing the canyon, not the back.