Factual error: At the end of the movie the cast is counting down to the explosion of the Krell furnaces. They reach zero and the furnaces explode. They see the light from the explosion just it happens. But they are 100 million miles out by then. The light would have taken over 8 minutes, about as long as light from the sun takes to reach earth, to reach the ship.
Factual error: Alexander's copy of Homer is a codex, or bound book, not invented for another 400 years or much used for 600 years.
Factual error: When the boy is crying because he's made to ride a pony, the Texas flag is made wrong. The top star point is toward the red stripe instead of the white strip as it should be. In other scenes the flag is flown upside down - the white stripe should be on top.
Factual error: When Rameses is casting Moses out into the desert, he stands in his chariot. The pyramids behind him is the Saquara pyramid, so Moses is being sent West into the Sahara, and not East into the Sinai.
Factual error: The movie's beginning takes place in 1868, yet all the men pack cartridge Peacemaker Colts (not available until 1873) and model 1892 Winchesters (not available unti 1892).
Factual error: When the filmmakers were choosing existing warships to play the roles of the ships in the battle, they didn't quite match up some of the details. The Graf Spee is represented by USS Salem which has three triple gun turrets - yet in the Captain's cabin is a photograph of the real Graf Spee which had just two turrets. Likewise, HMS Ajax is represented by a Sheffield class cruiser with four triple gun turrets - yet in the fire control area there are just eight lights to indicate guns ready to fire.
Factual error: Towards the middle of the movie when when the British submarine leaves port with the Man Who Never Was onboard, it is flying what appears to be an American flag. The flag is visible for about ten seconds and if you look closely, you can see the field of blue of the stars and stripes in the upper corner.
Suggested correction: The flag, as can be seen before submarine sails and then from a distance, is obviously the White Ensign.
Factual error: When speaking to a member of the the Royal Family in Siam (modern day Thailand), one have to speak "rachasap" or Royal Thai. The movie depicts characters speaking colloquial Thai to the King.