Continuity mistake: Mention is made that Pamela owns the brewery because she has just turned 21. During the scene with the video game, she says her birthday was October 21, 1959. Later, the lawyer for Bob and Doug establishes the movie's timeframe by mentioning her kidnapping on October 10, 1983, which would make Pamela almost 24 years old instead.
Continuity mistake: When the van flies off the end of the dock, the rooftop vent is missing in its entirety. When the van is seen at the bottom of the lake, the vent is now reinstalled.
Continuity mistake: The brother, disguised as a doctor, enters the hospital and kills a patient by injecting him with some kind of poison. The problem is that the huge hypodermic needle stays at the same fluid level before and after the injection and afterwards has a quarter inch of air in it.
Continuity mistake: When Bob and Doug discover the control room, the lab assistant is unconscious in his chair. Bob touches his back to see if he is all right, and the assistant falls forward and then carefully lays himself down on the floor.
Continuity mistake: There is a scene between Brewmeister Smith and the brother. Smith is mad at the brother and lifts him off the ground by his earlobe. There are all kinds of problems with this little scene. First, Smith doesn't so much as flinch with the act of lifting a heavier man off the ground one handed. Secondly, I'm not sure an earlobe can withstand the weight of a 250 pound man. Thirdly, Smith doesn't even flex a muscle at the process and the brother obviously just raises up on his tip-toes.