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)
Plot hole: It's one thing to have a small amount of liquid nitrogen (about the size of a standard propane tank, by the looks of it from the Fridge scene), but where did the gallons upon gallons of it during the climactic flood scene come from?
Factual error: When the Toad's foot breaks the pipe of liquid nitrogen, it should have frozen the water immediately, but it takes a lot more time to allow the wave to get closer.