Factual error: When it's 1969 we see a boy (I'm not sure which one so you'll have to look) riding a Shwinn Sting-Ray Krate Grey. That bike didn't come out until 1971 and they only made them that one year. (00:02:45)
Factual error: Various Sydney landmarks can be seen throughout the movie (although the Centrepoint Tower and the Monorail play major roles). There are also some cars that have right-hand steering wheels despite the story being set in California, and some Australian model traffic lights (foot-long black cover with a grey pole) can be seen when the Scorpion bot destroys a car in front of the Rangers. (01:06:00)
Factual error: When the soldiers are asked to find out what gifts Andy is getting at his birthday party, the set out down stairs with half of a baby monitor. Well, any parent who owns one knows that there are 2 pieces to a baby monitor. One half (the larger half) is the receiving end (that takes in the noises) and a smaller half which is the transmitting part (the half that sends out the noises). The half that the soldiers take downstairs to talk through is the wrong half. They take the half that the noise comes OUT of. So, really, they should NOT be able to speak into this part - in real life, they'd hear what was happening up in Andy's room. (00:09:18)
Factual error: The equation written on the board does not come out to be "11", in fact, it's not really solvable because it doesn't have 2 sides, just a "?" on one side.
Factual error: John Smith's (voiced by Aussie, Mel Gibson) accent changes and also fades in and out during the course of the movie.
Factual error: When Napoleon is up in the air in the basket held up with balloons, you can see the Sydney Harbour Bridge, however on his adventures, he goes past Eagle Rock, which is not near the city. Also he meets a Frilled-Neck lizard, which is found in a different state to Sydney.
Factual error: How could Brian get a cold after he was outside in the rain for a minute and was dried off right away?
Factual error: Many times in the film, the Nutcracker is shown to be standing at rest, but with its mouth open. It is at rest with nobody touching it, so its handle/lever would be in the down position by gravity. Yet the Nutcracker’s mouth is open. If a nutcracker is sitting at rest with the handle down, the mouth should be closed.
Factual error: At one point in the film, Morgan calls out "Riflemen, to me!". The film is set in the late 17th century. Whilst rifling had been invented prior to this date, it was still rarely used except on the most expensive weapons, and even then mostly used by specialists. It is highly unlikely that all, if any, of the pirates would have been armed with them, especially in the close quarter fighting they would have been expecting. The pirates would be more likely to be armed with the more common smooth bored muskets of the period, so "Musketmen, to me!" would be much more likely to be correct.
Factual error: George is paid an extra $15,000 to move out of the house in ten days and he his paid in $1,000 bills. Although $1,000 bills do exist, they are not used by private citizens. They are only used by large banks.
Factual error: Calamity Jane was not Pecos Bills love interest. According to legend Pecos Bill was married to Slue Foot Sue another tall tale. Whereas Calamity Jane was an actual historic figure.
Factual error: When Calvin is invited to sit at the table with King Arthur and his daughters, as he is sitting down you can see that King Arthur is wearing a t-shirt under his robe.