Continuity mistake: At the end of the escape scene, Rita makes her way to the street by jumping down from one object to another. The last thing she lands on is a hammer handle sticking out of a filing cabinet. When Roddy attempts to follow her, he falls on the same objects that she jumped on to. The last thing he lands on, though is the head of the hammer that was absent from the handle when Rita jumped down. (00:25:55 - 00:26:40)
Continuity mistake: During the scene where Rita hugs Roddy for giving her the jewels,When it shows Rita's back, Roddy's hand skips from Rita's upper back to Rita's lower back. (01:00:30)
Continuity mistake: When the family is leaving the house at the beginning, the girl puts a lot of food in the bowl inside the cage. She even leaves the box over the food. Suddenly there's an open shot and the food and the box are not longer in the cage.
Continuity mistake: In the beginning, during the "James Bond" sequence, Roddy shoots a dart at the DVD to knock it into the DVD player. From behind the DVD, it falls forward, from the front, it falls backwards (which makes more sense considering he shot it from the front).
Continuity mistake: When the rat first arrives at the sewer, there is a slug that screams and tries to run away. Next shot he has totaly disappeared with nowhere to go.
Answer: Not really, when you consider it's a fake so it probably very light, and only falls an inch or two (given the height of the average rat).