Continuity mistake: The cookie Calvin rubs all over his body only has raisins on the top left of the cookie. When the grandfather picks it up they are neatly in the center: not the same cookie.
Factual error: When Calvin is examined by the doctor, the doctor notes that he has a large scar on one side, possibly as a result of an appendectomy. The scar is 1) very sloppy; 2) pointing the wrong direction; and 3) on the wrong side of the abdomen for an appendectomy scar.
Continuity mistake: When Calvin is sitting in the seat which has elastic ropes attached to it, he jumps forward to grab the grandfather's food. When he grabs the sausage, which is the last thing he eats, there is a slice of orange on the plate, but when the grandfather looks down there isn't. You can see this without stop motion, but it's much clearer when you do pause it.
Revealing mistake: When the dad inserts the rectal thermometer into Calvin and he looks up, the CGI head is too obvious, especially when he is putting his head back down on the bed.
Continuity mistake: When the old man is ready to eat some cookies in front of the TV, the total number of cookies changes from 5 to 6 between shots.
Continuity mistake: When Percy is being interrogated by the other criminals, the objects on the table keeps changing place or disappearing.
Continuity mistake: When little man gets into a fight with the guy in the dinosaur costume, he punches him in the nose and starts bleeding. When they show him again on the ground there's no blood on him at all.
Visible crew/equipment: Early in the movie, in the scene where the 2 guys steal the large diamond, the 'little man' (who is black, and wearing black gloves) cuts a hole in the wood around the diamond, using power tools. In the shot where he replaces the wood (after taking the diamond), you can very see a white, gloveless hand in the bottom left (near the drill hole) is putting the piece back in place.
Continuity mistake: In the beginning when Jimmy is singing he leans down to Vanessa very briefly and is not singing.
Continuity mistake: The mud stains on people's clothing is constantly changing size, location and colour during the game of football.
Revealing mistake: Numerous times throughout the film the CGI used to show Calvin's height is very obvious. An early example is when he climbs on Percy's back to look in the window.
Continuity mistake: At the hockey game, Greg is seen when Calvin is biting the player's ear, but when the player starts stomping Calvin, Greg is no longer seen.
Character mistake: At the end of the movie, Darryl tells Calvin they don't have a back door. There's a back door in the kitchen and another door that goes back to the backyard patio.
Continuity mistake: Calvin gets a bruised face at the hockey game. The next day, they are gone. Bruises don't disappear overnight.
Continuity mistake: At the hockey game, the girl has 4 full cups of beer. She gives one to Darryl and his 2 friends, and the guy sitting beside Calvin. When she turns around, there's one full cup still on the tray.
Suggested correction: Is was an empty cup that the Calvin finished and she put it up there, it wasn't full.
Continuity mistake: When Calvin is mad at his grandpa for having his cookies, there are only three cookies on the plate, but in the next shot there are five cookies on the plate.
Character mistake: At the end of the movie, Darryl tells Calvin to be quiet so his wife won't hear them talking. She's not even home. She went to get her dad at the nursing home.
Continuity mistake: During the robbery scene, Cal throws a dog out the window at a old woman, but instead she picks him up off the ground.
