Visible crew/equipment: When Mrs. Hess' TV is off, if you look closely you can see the camera filming the shot and its stand.
Continuity mistake: When one of the criminals confirms her position as "4th house, moving to the alley," the shot moves to Alex running from one window to the other, with nothing in his hands. He goes to push open the window and the shot changes again. Alex now has the car remote control as the window opens.
Visible crew/equipment: Alex fixes the TV to show a camera picture. The next scene when two of the criminals pull up in the car next to a mirror, a crew member is blatantly visible in the reflection, if you look closely on the left hand side.
Continuity mistake: Alex starts turning off Mrs. Hess' TV from the attic. The ornaments in front of the TV move between shots at least twice, in consecutive shots.
Factual error: In real life (there are a couple of scenes like this) snow doesn't fall from the sky at the intensity it was from clear skies.
Continuity mistake: In the scene where Stan is bouncing his basketball, Alex's grasshopper is crawling around on the floor. Notice the bug is a brown type of a color and then when Stan squishes the grasshopper it is green on the bottom of the basketball.
Continuity mistake: The scenes where the bad guys get into Chicago are in daylight, but when they are "chasing" the taxi cab it is nighttime.
Continuity mistake: When Alex first takes out the bubble-squirting gun and threatens Olek Krupa's character with it, the muzzle looks like what one might see on a real gun. However, when we get a closeup of it after Alex shouts at Olek Krupa and chases him away, the muzzle has a gaping hole in it, because it's a different bubble-squirting gun.
Continuity mistake: Near the beginning, Beaupre and Co. follow a taxi driver to its station and we see it park. It pulls right up to a metal fence. However, when Jurnigen and Unger approach the taxi driver a moment later we can see in the background that the fence is a good distance away from the car.
Other mistake: When Jernigan says, "Gotcha" when Alex comes into the room and Jernigan falls, it shows him falling but his expression doesn't seem like he is actually scared.
Continuity mistake: The main bad guy has Alex cornered in Mrs. Hess' garage. Look at the clear plastic cup behind Alex. One shot the cup is upright, the next it is on its side.
Continuity mistake: When the villain with the long hair is being electrocuted by the wire outside the front door, in a close up shot his ski pants are on fire, then in a further away shot, they are not, then in another close up they are on fire again.
Audio problem: When the police are called for the first time, two officers burst into the house and are confronted by a dog. The alarm strangely stops three seconds after bursting in.
Continuity mistake: Alex puts the present down to take off his hat and scarf, by the front door. Between shots the present moves a few inches closer to the bag next to it.
Continuity mistake: A little way into the film, Alex is talking to his mum in bed whilst she is applying lotion to his chickenpox. One moment his shirt is open, the next it is buttoned up and closed, but there was no time for his mum to do it up, it happened in a split second.
Continuity mistake: In the scene where Alex's mum is about to leave his room after applying lotion to his chest. Alex's hair is slightly scruffy - when the shot comes back to him after being on the mum his hair is combed and neat.
Continuity mistake: When Miss Hess leaves the plane after landing in Chicago, she takes a scarf out of the Parisian bag she has accidentally picked up. Surely she would have noticed the items within the bag were not hers when she put the scarf in the bag?
Continuity mistake: Mr. Beaupre is talking to Alex in the garage, and Alex walks backwards away from him, he nearly touches the wooden shelf behind him. When it cuts to a wideshot Alex is now much further away from the shelf, and when it cuts to another closeup he once again walks back into the shelf.
Continuity mistake: When Alex revs the toy car backward to drag the rug over the stairs into the other room, we can see in one shot the rug only reaches the bottom of the second step, whereas in the next shot of the car coming down the steps, the rug is now further down and you can see that a ramp has been put under it so the car does not fall over.