Continuity mistake: While Mr. Klimer is forcing Debbie into the car, he for some reason seems to have a Charlie Chaplin-esque moustache which he doesn't have in any other point in the episode.
Revealing mistake: When Mr. Klimer is chasing Debbie while she says "It smells like poor people", her face is back to normal instead of disfigured.
Revealing mistake: When Mr. Klimer is forcing Debbie into the Oblong's car, her arms disappear for a single frame.