Continuity mistake: When Corporal Allen pulls Private Hitch off the ramparts when Hitch is shooting at Zulu's in the hills with his pith helmet on backwards, Hitch gets shot in the leg, and Allen pulls him in. Allen is shot in the chest, he clutches his chest, falls inside ramparts with blood underneath his clutching hand. When you see him after camera cut he is clutching the OTHER side of his chest.
Continuity mistake: In the scene where Michael Caine shoots at the cheetah, you can see the trainer in the clump of trees beckoning the animal on.
Continuity mistake: Even though Lt. Bromhead shot a cheetah, the porters carry a dead leopard back to camp.
Factual error: Lieutenants Chard and Bromhead were both rather elderly for their ranks (in their mid-30s) and Bromhead's career had begun to suffer due to a hearing problem. Like most members of the garrison, both had full beards.
Factual error: A bit of dramatic license was taken by the scriptwriters. Though portrayed in the film as a skiving drunkard, in real life Private Hook was considered a model soldier who was a lifetime teetotaller. Hook was receiving good conduct pay at the time of the battle.
Factual error: Colour Sergeant Bourne was in fact rather a small man (which Nigel Green is not) and was actually, in his early 20s, the youngest colour sergeant in the British Army.
Continuity mistake: The porters carrying the Leopard across the river pass by Baker. The next cut shows them approaching him.
Factual error: Assistant Commissary Dalton, portrayed as a bit of an upper-class twit in the film, was in actuality a former infantry quartermaster sergeant and the most experienced soldier in the garrison. He helped to plan the defense.
Other mistake: In the scene when the Zulu warriors have broken through the roof in the hospital. The British make a hole and escape through it. You can clearly see the hole that they are going to cut open because it is a different color
Continuity mistake: After the Zulus' final charge which follows the rendition of "Men of Harlech", they appear on the hills round Rorke's Drift to give their salute to the garrison before leaving. In one shot, filmed from behind the Zulus, both buildings, church and hospital are standing even though the hospital burned down during the battle. Seconds later in the next shot of the post from the hills, only the church is standing and a column of smoke rises from the ruins of the hospital. I believe that some scenes were filmed of the Zulu Impi crossing the Buffalo River and marching to Rorke's Drift, but were cut from the film. The first shot mentioned above could be one of these.
Deliberate mistake: This is a mistake which is a function of the limitation of the special effects at the time and what the censors would allow in the cinema but the wounds suffered by the Zulus do no justice to the horrific injuries that the Martini Henry rifle would have caused. The Martini Henry fired a big .45 inch soft nosed bullet that usually shattered on impact. It would have caused massive gaping wounds rather than the little red dots and trickles of blood shown on the Zulus and left many of them limbless as the bullets tore off arms and legs.
Factual error: The 24th is identified as the "South Wales Borderers." In 1879, the regiment was the 2nd Warwickshire. It did not become a Welsh regiment until 1881.
Factual error: The Swedish missionary Otto Witt is portrayed as a drunkard who encourages the soldiers to abandon their posts. In reality Otto Witt helped the defense by helping to build the barricades. He later volunteered to assist as a lookout on the nearby hill. He departed before the battle to join his wife and two daughters at a nearby farm.
Continuity mistake: In the Diamond DVD, chapter 4, time 01:36:04, Stanley Baker is shown in a far shot breaking open his revolver and emptying the spent cartridges. Without reloading, he does it again seven seconds later in a close-up shot.
Continuity mistake: During the lull before the attack on the hospital, when Pte. Hook walks over to the doorway to speak to somebody, his suspenders are dangling down from his waist. A minute later, when the camera angle changes, his suspenders are suddenly up over his shoulders. Then, when the camera angle changes again, his suspenders are back down again.
Continuity mistake: When Zulus are battering down the door leading to Hook's bunk and the soldiers inside are escaping through a hole they knocked in the wall, at some point a blazing log falls across the hole. Some shots later, it's gone.
Plot hole: There must have been a shortage of Martini-Henry rifles for this production, for in the climactic charge scenes in which the three ranks of British soldiers deliver volley after volley into the Zulu masses, the soldiers closest to the camera are equipped with lever action Martini-Henry's but those further back in the line can be seen pulling up and back on bolt action rifles.
Deliberate mistake: The Zulus sniping on the defenders from the mountain are armed with Martini Henry Rifles implying they were taken from the dead at Isandlwhana. This couldn't have happened as the Zulus attacking Rorke's Drift did not fight at Isandlwhana, they were only the reserves. The looting of the camp was done by those who fought there. The Zulu snipers used old muskets.
Factual error: After the battle, the remaining Zulus left the field without making a sound, unlike the movie.