Tom Green performed most of his own stunts, including the skate boarding scenes and the house scene. The studio was against him doing any of the stunts because if anything happened to him, they'd lose the lead actor AND director.
When Darren breaks his leg skateboarding on Gord's half-pipe, Gord kneels down next to him. Gord's dad comes out and stands by him screaming. A close-up on Darren shows a man in a striped robe kneeling by him. Gord's dad, in the striped robe, is still standing up.
At the factory when Gord is clowning around on the conveyor belt, he takes a salami from the end of a row. Later it shows a salami missing in the middle, not at the end of it.