Davy, George, Thimblerig, and Bustedluck are seen walking with 3 horses between them (Bustedluck had lost his horse when he was thrown from it just before his first encounter with the others, one of the instances of "busted luck" that led to his nickname from George). They stop for water and then suddenly they are riding four horses.
The Texas flag raised over the Alamo is first seen in near-tatters, with the three colored sections almost completely separated from one another apart from small connected bits at the very top. It is later seen to be nearly intact, if frayed and with a few small holes in it. It is then seen again in its original, much more grievous condition.
Davy Crockett arrived in Texas with about 65 men, mainly recruited from Little Rock (this biopic only briefly mentions a stop in Little Rock), not the two seen here. He took an oath of government well before making the trip to the Alamo, and arrived with about 30 Tennesseans, not just himself and the ragtag threesome seen here.
William Travis is shown as a reluctant leader and very deferential to Jim Bowie. In reality, Travis and Bowie's relationship was contentious, with both men making a claim to leadership of the fort. An agreement was eventually reached where Bowie, a colonel in the Texas volunteer army, was placed in command of all volunteers in the fort, while Travis, a lieutenant colonel in the Texas Army, was in command of the "regulars" or commissioned officers. Bowie felt that his rank of full colonel superseded Travis's rank of lieutenant colonel despite Bowie's rank being that of a member of a militia and Travis's being of a recognized army. Travis was more than ready to assume full command when Bowie's health began to fade.
Flintlock rifles and pistols cannot be fired straight down unless the bullet is patched, as the bullet (really a lead ball, not what is thought of as a bullet in modern times) could roll out. None of the defenders of the Alamo are seen patching their shots (which involves placing a small piece of fabric or paper into the barrel along with the bullet to prevent just such a thing) and therefor would not be able to shoot straight down at the Mexican soldiers as they are seen doing in the final sieges.
The Alamo is defended and inhabited here exclusively by male soldiers. In reality, the Alamo was an active mission before the siege and there were a number of women and children present, who hid in the inner sanctum and largely survived the battle (though a few were wounded or killed).
During the first battle depicted between the soldiers of the Alamo and the Mexican army, there is a mixture of nighttime exterior shots, day-for-night exterior shots, and studio shots, with noticeable differences between the visual quality and lighting of the three types of filming techniques.
During the attack on the Alamo that comes after George's return, the Mexican army is shown approaching in exterior shots with very obvious day-for-night shooting, while the shots on and around the Alamo at interior shots with a darkened sky backdrop.
Two soldiers are at ground level defending the Alamo when the Mexican army breeches the main entrance and charges in. None of the Mexican soldiers have their guns in a firing position, but shots are heard and the two defenders crumple to the ground anyway.
Stock footage of wildlife is used to supplement sequences involving wild animals. The footage is of a noticeably different quality than the new footage.
When Davy and his companions are approaching the Alamo, chased by the Mexican army, there is one shot in which they ride down a fairly steep embankment. The footage his been sped up, as is evidenced by the unnaturally quick rising and dissipating of the dust the horses kick up.