Continuity mistake: The lights on the Do Lung Bridge keep changing between shots. There are many more burned out light bulbs in the shot of Captain Willard and Lance as they leave the boat then there are when we first see the bridge or when the bridge is in the background as they walk past it. (01:42:15)
Continuity mistake: Docked next to the sampan Chief Phillips yells at Chef to, "Get on that boat," there's a shirt on the pole with the blue lights on it in the front of PBR. This shirt is in some of the shots and not in others throughout this scene. (01:36:00)
Audio problem: Just before the flare flies into Colonel Kilgore's helicopter, Lance says, "Nice shot, Bill" but his lips are not moving. (00:41:50)
Revealing mistake: In a close-up of Captain Willard's face as he reads about Kurtz' "Operation Archangel" the sweat droplets on the band-aid are exactly the same as the droplets on his skin. The droplets were obviously sprayed on his face as Band-aids don't sweat. (01:02:50)
Audio problem: As Bill Graham comes out of the Playboy helicopter he takes a microphone and says to the audience, "how ya doin' out there, I said how ya doin' out there?" and his lips are not in sync with what he's saying. (01:06:35)
Continuity mistake: During Willard's bout of insanity in the opening scene, we see him doing karate or something in front of his bed and there's blood visible on the sheets. Yet that is not supposed to be there until he smashes the mirror (half a minute later) with his hand and then runs the blood over the bed and his face. (00:06:03)
Continuity mistake: As they leave the USO show the Green Beret security guard gets into the helicopter before Bill Graham. In the next shot he gets in again. (01:10:10)
Continuity mistake: When he first opens the package from his mom Clean is holding a brown envelope with a cassette tape in it. Three shots later as he reads the letter from his mom and listens to the tape, the package has changed to a white carton. (01:51:05)
Continuity mistake: Kilgore walks towards the beach and notices that the wind is starting to blow on shore and ruin the surf, and intense red green and yellow smoke canisters appear on his left between shots. (00:50:00)
Continuity mistake: On the dock as he talks to the sergeant about getting some Panama Red, Chef's mustache is combed downward and shaved more around his upper lips than it was in the shot of him before they docked at Hau Phat where it's bushier and combed off to the sides. (01:05:00)
Continuity mistake: As the people on the Vietnamese sampan hand their papers over to Chef, Clean is holding the 60 caliber machine gun with both hands. In the next shot he's holding the bullets in his left hand. (01:35:35)
Continuity mistake: When they first meet, Colonel Kurtz says to Captain Willard, "Have you ever considered any real freedoms?" and the Captain's shadow appears on the stone column to the right of the Colonel. The Captain is kneeling down and hasn't moved from his spot, but when we saw this column before his shadow was not anywhere near it. (02:39:25)
Continuity mistake: Before they board the sampan Lance says, "It's clear, Chief," and we see a wide shot of the sampan and PBR. No one goes near it, but for just one shot the dress on the clothesline is rearranged. The two straps it hangs from are pushed together. In all the other shots the straps are wide apart. (01:35:40)
Continuity mistake: In the close-up of Dennis Hopper giving the Captain some water he holds the ladle between his first and second finger. In the next shot he's holding it between his thumb and first three fingers. (02:42:45)
Continuity mistake: Harrison Ford lights up his cigarette and Captain Willard says, "I'm not presently disposed to discuss those operations sir." Jerry is sitting with his back almost up against the wall. In the next shot as he takes a puff from his cigarette he's moved and is now leaning forward. (00:10:45)
Continuity mistake: As the VC first hear the helicopters coming an old woman in a pink top with a baby runs across the schoolyard. In the next shot she disappears and most of the school children have changed positions. (00:39:05)
Continuity mistake: The paint on Captain Willard's face changes many times throughout the movie. Two very noticeable examples are right after he kills the colonel, where the paint is almost entirely off his face, and several shots later as he leaves the temple heading back to the boat where his entire face is painted a much darker green then before. (03:09:20 - 03:11:50)
Continuity mistake: As they get close to the French plantation dock we can see inside the building and it's dark. Several shots later as Captain Willard is walking around inside the building it's lit up from the inside. (01:56:00)
Continuity mistake: As Chef pulls the Vietnamese woman out from where she's hiding you can see the shadow of Lance's gun barrel as he stands there holding it on her. In the next shot Lance gets up from a seated position in front of the boat. (01:36:20)
Continuity mistake: In the first few scenes with the air cavalry commander, his black hat has a lieutenant colonel rank and a small crossed-sword emblem on it. Later, as his helicopter lands on the beach, his hat has no rank and is emblazoned with a very large crossed-sword Cav emblem. (00:27:26)
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