When Stan is pointing the sniper rifle at Francine, the end of the barrel is the same glass color as the telescopic sight for most of the scene. It changes to the correct metallic color by the end of the scene.
When Ted Feedler bites his thumb off, it is missing for the rest of the episode but for a brief moment, as he's falling to the mat, you can see it intact.
When Stan gives Steve his allowance, the counter behind Steve alternates from being tiled to a flat top.
The arrow on the refrigerator Threat Level Meter is missing in several scenes.