Continuity mistake: The first time Vern goes through the hedge, he enters into the backyard of a house, but when he returns via the hockey stick, the hedge borders the street, not the back yard. (00:13:50 - 00:15:30)
Continuity mistake: When the Depelter Turbo is used to capture Gladys, Dwayne and Vincent, the beam of light that goes straight up shows us that is is coming from a city (Chicago, perhaps?)just south of the tip of Lake Michigan. However, when RJ opens the bag of tortillas, the orange mushroom cloud shows his location as being farther to the west and south.
Continuity mistake: As RJ rifles through his backpack looking for the whipped cream to make Hammy appear rabid, he tosses several items out and/or over his shoulder, most notably a toilet plunger. The items are gone when Vern confronts RJ in the same spot moments later.
Continuity mistake: In the scene where Gladys (the president of the Homeowners' Association), the exterminator man, and the bear are being hurt by the contraband contraptions designed to exterminate the animals, a bright light develops, and the animals watching have to put sunglasses on. When the light disappears, Verne and RJ have tan lines everywhere except where their glasses were. But in the next shot of the animals (they're celebrating), Verne and RJ's tan lines have disappeared.
Factual error: In the beginning when the animals are waking up from hibernation, it shows Ozzie and Heather running out of the log, which shows they hibernated, but opossums don't hibernate.