Factual error: Toshiro Mifune's character, Kikuchiyo, travels to the bandits' camp and steals one of their two remaining fuselock muskets. Shortly afterward, the bandits fire twice at the samurai within five seconds with their last firearm. A fuselock takes as much as two minutes to reload, prime, and fire.
Factual error: The giant squid's tentacles aren't shaped like ones in the real world are.
Factual error: In the shot where the three officers ride the aircraft elevator from the hangar deck to the flight deck after arriving aboard the admiral's carrier, you can briefly see some of the aircraft parked on the hangar deck, and they are jet aircraft. The aircraft have pointed noses, no propellers, and the fuselage shape and markings are consistent with first generation Navy carrier jets. These types were not in service until the mid-50s (See "Bridges of Toko-Ri").
Factual error: There is a shot of a large arena where gladiatorial combats take place. Arranged around the top of the arena are a number of classical statues, one of which is Michelangelo's statue of David circa 1505 AD, 1,465 years too early!
Factual error: After the plane takes off from Hawaii, bound for San Francisco, there's a long shot of it flying among the clouds, with the left side well lit by the Sun. If the plane is flying east, in the northern hemisphere, then the Sun would be in the southern sky, illuminating the plane's other side.
Factual error: When David talks to Linus about the consequences of calling off his engagement with Elizabeth he says that their father would take to the bottle and smoke six coronas. Throughout the movie the old Larrabee smokes one churchill after another, but not a single corona, which is significantly shorter than a churchill. (01:02:05)
Factual error: Jeff has been in a cast (for a broken leg) for seven weeks and has been in his apartment for most of that time. He tells his boss that he has one more week before the cast is removed and can then immediately go back on assignment as a photojournalist. By this time he should have been transferred to a walking cast and be using crutches instead of confined to a wheelchair, but he is still wearing a full leg cast that goes up to and around his waist.
Factual error: At the beginning of the movie, Forney, who is an enlisted man (a chief petty officer), replies to an officer's orders with, "very well, sir." Officers say "very well" to enlisted personnel, but for an enlisted man to say "very well" to an officer is a serious breach of naval etiquette.