John Wayne later said he regretted starring in this film as the director was a Communist.

When John Wayne heard that Ben Barzman and Edward Dmytryk were openly belittling the religion of the film's technical advisor, Colonel George S. Clarke (who had commanded the 57th Infantry Regiment of the Philippine Scouts during the Battle of Bataan and was roughly Wayne's real life counterpart), and mocking him with renditions of the Internationale, he confronted Dmytryk, asking him if he was a communist. Dmytryk replied that he was not, but if "the masses of the American people wanted communism, it would be good for our country". Though Dmyrtyk denied he was a communist, Wayne felt that he was by his use of the word "masses". By contrast, Barzman's wife Norma recalled Wayne being friendly with her husband, with Wayne hugging him and calling him a "goddammned communist", to which Barzman jokingly replied that Wayne was a "fascist". Wayne also developed a friendly relationship with Dmytryk, respecting his talents as a director. The actor was genuinely perplexed as to why Dmytryk, who was well-paid and enjoying the fruits of American democracy, would have such sympathy for communism, asking him, "Jeez Eddie, what's your beef with America?"

The United States had annexed the Philippines in 1898 along with Puerto Rico and Guam.

John Wayne later tried to have director Edward Dmytryk blacklisted from Hollywood.

As John Wayne refused to use a stunt-double in the movie, director Edward Dmytryk and screenwriter Ben Barzman wrote scenes for Wayne with dangerous stunts so that he would want to use a stuntman. Not even this deterred Wayne who still did the stunts.

Continuity

An M4 Sherman tank, standing in as a Japanese tank, approaches a bridge and is blown up. When the smoke clears, the wreckage is now that of an M3 Stuart.

During the climatic battle, we see Quinn crawling through the mud with his Thompson as a Japanese truck is bearing down on him. Wayne peppers the truck with machine gun fire, causing it to crash. A second later you see Quinn join up with Wayne and he's perfectly clean.

When Maximo learns of his father's death, he runs into the room and is weeping copiously, but throughout the scene, his shoulders and body never move at all, so the sounds he's supposedly making don't match his body language at all.



Factual errors

Imperial General Headquarters regarded Homma as not aggressive enough in war (resulting in the high cost and long delay in securing the American and Filipino forces' surrender), and too lenient with the Filipino people in peace, and he was subsequently removed from his post on June 9th 1942 and returned to Japan. In the movie when they are discussing the possibility of Filipino independence with Dalisay Delgado, Homma, would have been in Japan at this point in time.

Andr?s Bonifacio only had one son who died in its infancy. Thus, there couldn't have been a grandson of Andr?s Bonifacio.

An American submarine surfaces to deliver guns and the sailors who help paddle them ashore are clean-shaven. However, water was in limited supply on board a submarine, so sailors grew beards.

Towards the end of the movie the narrator was talking about where the Yanks had landed he mentions Midway. Midway was always in American possession during World War Two.



Revealing mistakes

A long shot of the truck carrying the Japanese soldiers and the boy Maximo driving along the mountain road is repeated twice (the truck is seen passing in front of a hill headed toward the right of the screen, then the same shot is repeated a few seconds later).

At the beginning of the film, when the POW camp is liberated, a soldier throws a grenade against a portion of the fence. It explodes, but it is the adjacent section that ends up being breached.

When the guerrillas listen to the stolen Japanese radio, there is no external power source to make it work.

Plugs can be seen in the barrels of the Thompson sub-machine guns which make them fire fully automatically with blank rounds.



Miscellaneous

Colonel Madden refers to encounters with the Katipunan (a Philippine revolutionary society) and the Philippine - American War, which both ended in 1902. This would make the Colonel Madden character about 30 years older than John Wayne, who was born in 1907 and just 37 years old during the filming.

When the Australian radio officer types the message he's receiving from the Phillippines, he spells the word "organization" using the American spelling, with a "z". An Australian would use the British spelling - "organisation", with an "s" - although, it is possible he simply wrote "z" because he was quickly transcribing the Morse Code signal sent by the Americans.



Audio/visual unsynchronized

At 0:13:30 when Col. Madden says "They're actually bridging that barbed wire with their bodies", John Wayne's lips aren't moving. At 0:13:50, before Madden is blown out of his foxhole, Wayne is saying something but his voice is not heard.



Crew or equipment visible

Before Col. Madden (John Wayne) is blown out of his foxhole by a munition, the wires that pull him up are visible.



Character error

Miss Barnes asks Col. Madden if, after he avenges the hanging of Senor Bello, he would erect a sign in his honor quoting a Filipino poem that mentions several kinds of trees, including a cypress. Madden and his men do so, but the on the sign the word cypress is erroneously spelled "Cyprus", like the Mediterranean island.