Factual error: When Harry and Sally are driving away from the University of Chicago at the start of their road trip there is a long shot of them driving on Lake Shore Drive, but they are heading south towards the city with the lake on their left. If they were leaving the city from UofC, which is in Hyde Park, they would already be driving away from the city on Lake Shore Drive.
Factual error: In the beginning sequence where they show the sperm first fertilizing the egg, it is biologically incorrect - only the head part of the sperm enters an egg, everything else stays on the outside and eventually dies off.
Factual error: At the end of the film, when Ursula has Triton's powers, she creates an enormous whirlpool that pulls wrecked ships off the ocean's floor. Prince Eric boards one of the ships that is being swept along with the whirlpool's currents, then turns the rudder hard to steer the ship into Ursula. Not possible - in order for the rudder to change the course of a ship the vessel must be moving faster than the current.
Factual error: When Bigfoot is about to drive through the car dealership it squeals tires with a high pitched squeal. IF it could spin those big meats it would be a deep hound dog like bark. (01:40:40)
Factual error: When Diane visits her father in prison, she hands him a pen, but visitors in prison are very closely searched - no way could a visitor give a prisoner a pen of any kind (they're contraband for prisoners as they can be used as weapons), let alone a heavy pen like that one. Even if he were in a minimum-security prison (which his orange jumpsuit seems to indicate he's not) this rule would still apply.
Factual error: An animal that lives in the deep sea cannot live in the open air above the water.
Factual error: In the opening scene when the guys are shooting craps, Little Quick shoots the large man squarely between the eyes. The man wasn't looking downward and it would have been impossible for a 4 foot tall kid to shoot a 6 foot tall man at that angle squarely in the forehead.
Factual error: In the scene with the Christmas decor in the front yard, all the trees are green as well as the grass and landscaping. Even in Louisiana at that time of the year, most everything would be dormant. (00:59:23 - 01:02:24)
Factual error: The song "Do You Wanna Funk?" by Sylvester, was released in 1982. However, the film uses this song in a dance club scene which the film identifies occurring on July 3,1981.