Factual error: The scene depicting Lieutenant Kilgore throwing out death cards onto the dead VC is not accurate. Real death cards were printed in packs that contained just the ace of spades on each card and had messages written in Vietnamese on the other side. (00:27:55)
Factual error: There are two factual errors in the helicopter attack scene - for the time frame of the war. First, the helicopters carrying troops would not have been armed with rockets or miniguns, these helicopters were called "slicks" and would only had door mounted machine guns. The helicopters armed with the rockets and miniguns were "gunships" and would not have been carrying troops. Second, a Huey is shown carrying in the Navy river patrol boat (PBR) slung beneath it. At over 16,000 lbs., a PBR weighs over four times more than a Huey of this era could have lifted. (Regardless of the REASON why these mistakes occur in the film, they are STILL mistakes.)
Continuity mistake: As the soldiers crash the stage the two rifles that the playmates were using in their dance have disappeared from the stage. (01:09:40)
Continuity mistake: Hubert de Marais says to the Captain, "because life, sometimes is very cruel, as you can see" as he hands him a plaque. At first he's holding it with his left hand then when he gives it to him, he's using both hands. (02:03:15)
Continuity mistake: There have been many shots of the surfboards as they flew to Vin Din Dop and they were all on the skids of the helicopters, now when Colonel Kilgore says, "do you wanna surf, soldier" we see the surfboards placed next to each lengthwise through the helicopter with their fins sticking out the side doors. (00:46:05)
Continuity mistake: Captain Willard shreds all of his notes on Colonel Kurtz and narrates to himself, "but the thing I felt the most, much stronger than fear, was the desire to confront him". In a wide shot of the boat we can see that the flag that covered Clean's body is back on top of the PBR. (02:26:20 - 02:27:50)
Visible crew/equipment: On the boat while reading Kurtz' file Captain Willard recalls Harrison Ford saying, "and follow every order, however ridiculous" while having lunch with the general earlier in the movie. If you look at the close-up of his eye you can see a cameraman and another person's reflection as they stand in front of him. (01:18:35)
Continuity mistake: A guy from Lazaro's boat throws a smoke canister that catches fire on the roof and Chef tries to put it out with a fire extinguisher. When we first see him trying to put the fire out his shirt is dry then the next time we see him his shirt is full of sweat. (01:16:40)
Continuity mistake: Chef and Miss May mess around in the helicopter as he says, "I can fly like the eagle". They start out facing the back of the helicopter then in the next shot they're facing the opposite direction. (01:31:40)
Continuity mistake: Colonel Kurtz drops Chef's head into Captain Willard's lap. At first the head has no blood on it but in the next shot when the captain realizes what it is Chef's face has blood all over it. (02:47:10)
Continuity mistake: As captain Willard, Lance, and Chef stand on the dock they hear the voice of a Frenchmen shouting at them. If you look closely at Chief Phillips on the bridge of the boat, he doesn't have a rifle in his hands but in the next shot he does. (01:57:20)
Continuity mistake: After he sees the sampan Chief Phillips says, "A junk boat Captain. We're gonna take a routine check," and Clean goes from aiming the 60 caliber machine gun behind him to not even holding it at all between shots. (01:34:30)
Continuity mistake: Captain Willard's is not carrying a holster when he approaches the bridge and talks to Chief Phillips about him not pulling over the Vietnamese sampan or when he's tying his shoes as he sits on the front of the PBR. He never leaves the front of the boat to get his gun but as Clean starts machine-gunning the sampan he's wearing his holster. (01:36:15)
Continuity mistake: The camera pans left as Colonel Kilgore has a beach party for the men at the end of the day. If you look closely at Lance he has two cans of the beer to the left of him, a Schlitz and a Budweiser. In the next shot the cans are reversed. (00:31:40)
Continuity mistake: Captain Willard and his two escorts get out of a helicopter and walk up to the guard post on the way to see General Corman. The soldier in the front is carrying some yellow papers in his right hand. In the next shot as they pass the guard the papers are in his left hand. (00:09:40)
Continuity mistake: As he spots the sampan Chief Phillips says, " Clean get on that 60" and the machine gun on the back of the PBR is aiming left towards the shore. In the next shot "Canned Heat" is pointing directly behind the boat. (01:34:25)
Continuity mistake: When we first see Captain Willard in the movie he's looking at the ceiling fan spinning above his head. There's only one fan above his head yet we see two different fans in the scene. The first ceiling fan has a different motor and the acoustic tiles show signs of water damage not seen on the second fan. (00:01:50)
Continuity mistake: In the beginning of the movie as Captain Willard dances around his room there's a red and white can sitting on the left of his mirror. It's there for two shots but then in the next shot when he busts the mirror it's not there and we see a box instead. (00:06:45)
Continuity mistake: During the beach party Captain Willard shows a map to Colonel Kilgore who says, "it's hairy, got some pretty heavy ordinance". We can see behind the captain and the closest person is about fifteen feet away but in the next shot a soldier drinking a beer is behind the captain and Chief Phillips appears walking up behind the colonel. (00:32:35)
Other mistake: During the arrow attack Chief Phillips says to Captain Willard, "you son of a bitch, you f@$". The closed captioning here is wrong and indicates he says "you bastard". (02:22:15)
Chosen answer: Kurtz was protected by political connections and his military record from being relieved of command, and the Montagnard people whose village he was in were considered American allies, so they couldn't just send a force in to kill him or relieve him of command, but an individual assassin. (The US Government's "official" policy is that they do not engage in assassination, which is why "this mission does not exist, nor will it ever exist").
Captain Defenestrator