Factual error: Why is Hilts not wearing a uniform? A serving officer captured behind enemy lines in civilian clothing risked being shot as a spy. If a prisoner's uniform was too worn or damaged to wear, it was routine for the German authorities to replace it - a P.O.W. in civilian clothes is an obvious escape risk. He is wearing a pair of tan chinos, a cut off sloppy Joe sweatshirt, both ridiculously anachronistic - Sixties hipster fashions - and nowhere even close to a World War 2 uniform. He is also wearing Army Type III Service boots - something that would never have been issued to a fighter pilot.
Other mistake: In the scene in which two Japanese Zero fighters bomb and strafe a PT base, shots of the attacking planes show them carrying no bombs. During the attack, they still drop around 20 bombs anyway, which is considerably more than the actual carrying capacity of the two planes.
Factual error: The weapons for this film, save for the American Krag-Jorgensen rifles, British Lee-Enfield MLE rifles, and German Mauser Gewehr 98 rifles, are completely wrong. The Russians, who had Mosin-Nagants, are portrayed with Mausers. The French are for the most part correctly poratrayed with Lebel Mle. 1886/93 rifles, but a few have Berthier rifles that weren't used until 1907. The Austro-Hungarians are portrayed with a mixture of Mausers and Berthiers when they would have had Mannlicher M88/90's or perhaps Mannlicher M95's. The Japanese are equipped with Mausers and would in reality have had Muratas. The Italians have a mix of Berthiers and Mausers, but would've used Vetterli-Vitali rifles. The Chinese Imperial troops and Boxers both have Gewehr 98 Mausers. Although they did indeed have Mausers, they had the far earlier Gewehr 71's and Gewehr 71/84's.