Continuity: As the movie opens, the little girl pours a whole box of rat food (and its box) into the dish at the front of Roddy's cage. When Roddy slides down to the front of the cage minutes later, neither the food, nor the upturned box is anywhere to be seen.
Continuity: At one point in the movie, Spike is incorrectly shown loosening a screw-on cap on a can of "Mixed Nuts" by turning it clockwise to remove it. When the lid pops off, the threads are clearly the standard, counterclockwise-to-remove direction instead. Similarly, when Spike is screwing the liquid nitrogen hose to the chamber Roddie and Rita are in, he turns it counter-clockwise rather than clockwise.
Factual errors: When the World Cup match is on, it says England are playing, but the flag on the screen is the Union flag which is for the United Kingdom, not England.
Continuity: When Rita is held upside down by whitey her rear (with pocket containing the ruby) is held facing away from Whitey. When the view switches to her face, this is also facing away from Whitey.
Continuity: Rita's belt. In the end sequence after Le Frog removes the master cable from Rita there is no opportunity for her to obtain a new belt, yet after the wave is frozen she is shown standing with Roddy suddenly wearing a black shoelace as a belt.
Factual errors: Several times during the film, someone gets thrown into the toilet which is shown to be almost full with water. However, British toilets have a far lower water level.
Factual errors: A number of times, the timer during the soccer game shows the timer down. Time is kept going up in soccer, thus making halftime 45:00 as opposed to 0:00.
Continuity: During the sequence with Roddy and Rita and the ruby, the "Jammie Dodger" passes by the same scenery on shore twice.
Continuity: Just before the Jammy Dodger plunges to its watery grave, Roddy and Rita chew through the twine that is holding the "Duty Free" plastic bag in place. They briefly are seen each holding a length of twine that is tied to one of the bag's handles. In the next shot, they are holding the handles for the bag itself, and the twine is never seen again.
Continuity: In the scene where Roddy falls onto the drawing at the city. Up above him the shot shows he landed in the middle, away from the trees in the picture. In the next shot where he gets up, his right leg is on the trees. How could he land in the middle then all of a sudden appear in another position?
Continuity: When Rita and Roddy are escaping from The Toad at the beginning, Rita jumps down repeatedly and ends on the handle of a hammer. When Roddy jumps/falls down the same path Rita went, the hammer has changed, and he ends on the head of the hammer.
Revealing mistakes: In the first toy car sequence (the one with the dolls), when Roddy brakes, the front bumper and license plate "clip" or "sink" through the floor.
Errors in geography: During the chase scene with Rita and Roddy vs. the other rats, the view towards the bow of the boat shows hanging signs. The reverse view shows the exact same signs in the exact same positions as if the boat were headed in the opposite direction
Continuity: As Rita and Roddy go floating past Le Frog and Rita grabs the cable, she is seen holding it in her hand, but in the next shot as she and Roddy are floating over London she is suddenly wearing it.
Continuity: When Sid first appears, he grabs two hotdogs off the counter and runs to the living room to watch TV. During the commercial for the soccer game, Sid throws a hotdog at the TV, leaving a grease smudge on the glass as it slides down. Later when the soccer game is on, no greasy mark remains. Given Sid's lack of cleanliness, it is unlikely he would have cleaned the TV by the time the game was on.
Continuity: The doll that Sid throws up in the air changes position several times after he discovers Roddy and Rita. It goes from being at his feet to being near the door to being several inches away from the door when he leaves the room.
Continuity: Roddy and Rita are about to be frozen by the Toad, but somehow Rita manages to: unscrew the tube, get herself and Roddy out, get Spike and Whitey into the freezing chamber and reattach the tube before the container fills with liquid nitrogen and get out of the fridge, pass the Toad without him noticing, grab the ruby and get half way up a flight of stairs to escape - all within a matter of moments.
Continuity: After Roddy is flushed down the toilet he is shown traveling down a pipe filled with water. Yet, when he is dumped into the main sewer line, there is no water coming out of the pipe.
Continuity: When Roddy and Rita are running away from the toad with the gem, The albino rat hit man has mittens on from the fridge, but they vanish when he uses his mate to try and slide down the rope.