When Willard is first shown a photo of Col. Kurtz the name tag on his uniform reads "Leighley". When Willard looks at the photo a second time, the name tag reads "Kurtz". (This is due to the fact the character's name was changed from Kurtz to Leighley and then back to Kurtz during the film's production after scenes using the Leighley name had already been shot.)
When the PBR leaves the Do Lung bridge, it has a radar dome. When they cut to the next river day scene, it doesn't. then, when chef hands out the mail, it does. For the rest of the trip, it's not there. Captain Willard even sits on where it should be when they reach Kurtz's lair.
In addition to Willard's Band aid on his cheek appearing out of nowhere, if you watch the laceration on his cheek, it is more healed early in the movie, and more raw later in the movie. Indeed, Martin Sheen has a scar at that location at the beginning of the movie in the hotel or apartment when the movie opens.
When attacking the village, Kilgore's helicopter has rocket pods on each side and no surfboards. When it lands it has surfboards on each side and no rocket pods.
"Canned Heat" is painted on the armor of the aft .50 MG. It appears and disappears throughout the film.
The maximum gross weight of a Huey helicopter is 10,500 pounds. It would be impossible for such an aircraft to lift a Patrol Boat, Riverine (PBR) which weighs anywhere between 15,000 and 19,000 pounds.
The Viet Cong's tracer bullets, seen quite often throughout the film, notably when the PT boat is "sprayed" with enemy fire, appear to be red in color. In reality, the Viet Cong used green tracer ammunition while the American's used red tracer ammunition.
When Willard is played the tape of Kurtz's transmissions, the male voice at the beginning of each transmission references them as originating from sectors "Peter, Victor, King" and "King, Zulu, King" respectively. By 1956, updates to the NATO phonetic alphabet included replacing "Peter" with "Papa" and "King" with "Kilo". During the time frame of the events of the film (at least the late 1960's), Army lettering code would not have referenced "Peter" or "King".
Many M16 rifles are shown with 30-round magazines installed. These were rarely used in Vietnam. The standard magazine of the Vietnam era was shorter, and held 20 rounds.
Capt Willard's audio narration says this about Lt Col Kilgore's unit: "The First of the Ninth was an old Cavalry division." But in military shorthand, 'First' would indicate the 1st Squadron (Battalion), and 'Ninth' would indicate the 9th Regiment. Neither of these is a division, which is a higher echelon organization. (The 9th Cavalry is part of the 1st Cavalry Division, though this is not stated in the film, and Willard is clearly talking about the battalion and regiment when he misidentifies it as a division)
As Willard flips through Kurtz's dossier, the voiceover says, "Third generation West Point, top of his class" while the dossier clearly reads, "Graduates West Point; second in class." Second is still reasonably considered "top of the class."
"One of the officers who briefs Capt Willard on his mission to find Col Kurtz is a full colonel named Lucas (Harrison Ford). At about 35 years of age, Lucas/Ford would have been too young to have held such a high rank during the Vietnam War (although this did happen in World War II)."
Since we do not know Lucas's age and given that his career would have spanned two wars (Korea and Vietnam) in which promotions are accelerated, it's entirely possible that a man in his late 30s would achieve the rank of colonel.
After the helicopter carrying the wounded child leaves, Lance's clothing has changed from his Army fatigues to a pair of shorts (this is because of a cut scene in which Kilgore gives him a pair of shorts to surf in. The scene was restored in the Redux edition.)
Lt Col Kilgore names off the four of diamonds twice.
"All right, let's see what we have. Two of spades. Three of spades. Four of diamonds, six of clubs...there isn't one worth a jack in the whole bunch. Four of diamonds..."
His deck of cards may be a random collection of cards with some duplicates and not a conventional deck. This would be especially likely if he did the "card calling" thing on fallen soldiers often, which his doing it here implies.
"All right, let's see what we have. Two of spades. Three of spades. Four of diamonds, six of clubs...there isn't one worth a jack in the whole bunch. Four of diamonds..."
His deck of cards may be a random collection of cards with some duplicates and not a conventional deck. This would be especially likely if he did the "card calling" thing on fallen soldiers often, which his doing it here implies.
The tape player that "Clean" picks up to play his mother's taped letter has no batteries in the bottom.
In the Redux version, there is a scene where Capt Willard is walking through a heavy downpour at the Playmate/Medevac helicopter site. His M16 is slung over his shoulder with the muzzle pointing upward. This allows rain to enter the rifle's mechanism, resulting in rust and and eventual jamming. Real combat troops carry their rifles with the muzzles down while in the rain to prevent this from happening.
As Willard reads the newspaper articles about Kurtz, the text of one article is about West German, Iranian & US discussions about nuclear energy. It has nothing to do with Kurtz.
When Cpt. Willard is approaching Colby, (the American soldier who was sent to kill Kurtz, but joined him instead) several of the women and children surrounding Colby look directly at the camera.
When Kilgore calls for the soldier to start The Ride of the Valkyries, the soldier starts the reel-to-reel tape. Unfortunately, none of the tape actually touches a playback head. Instead the tape is wound underneath a tension bar and on to the take-up reel.
There is a jump cut just as Willard lifts the pages of Kurtz's journal, before he sees the handwriting on one page.
On the back cover of almost all VHS and DVD releases of this film, Willard's rank is incorrectly listed as Lieutenant instead of Captain.
In Kurtz's dossier - on one of the pages, item #2 (that starts with "The fly-by formation of Corbra's" the word "prisoners" is misspelled as "prisonars".
In Kurtz's dossier - on one of the pages, item #2 (that starts with "The fly-by formation of Corbra's....." the word "prisoners" is misspelled as "prisonars".
While reading info about Kurtz, Willard eats a Hershey bar that clearly has UPC bar code on the wrapper. These were not included on Hershey bar packaging until 1976.
On the cover letter to Kurtz's dossier package, it is indicated he graduated West Point in 1946; 49-50 he was attending Harvard (completing his Masters degree); 50-51 he was assigned in Seoul, and 52-53 he was assigned to West Point ("..Teaches courses in American..."). However, on the last page that we see in the dossier (the form sheet, with the Dept. of Defense seal as the watermark) it is listed that he was at West Point 1941-45, and at Oxford University 50-52.
Before the Playboy/USO show where the crew is trying buy fuel from the quartermaster, the Playmate centerfolds hanging on the wall behind him are from the mid '70s, rather than the late '60s. The centerfold on the far right is Cynthia Wood, 1974 Playmate of the Year, who soon appears in the film during the USO show.
In Kurtz's dossier the cover letter in one section is a commendation to Col Kurtz for arranging a fly-by of Cobra gunships for a celebration or parade on "30 Aug 65." The first prototype of the Cobra gunship didn't fly until 7 Sep 65.
During Willard's briefing in Nha Trang, every time someone mentions the name "Kurtz" on the soundtrack, on screen they are mouthing "Lieghley", the original name of Col. Kurtz's character in the script during the early part of the shooting.
When pulling out from the Do Long bridge you can see the wake caused by the camera boat when the camera shows the boat pulling away.
Shadow of dolly and crew just before the scene with the news crew.
In Cambodia, when the crew is reading mail, then coming under fire and escaping, spray from the camera boat can be seen twice.
During the Courtyard scene, when the woman destroys the Huey Gunship helicopter. White special effects saw horses that allow the helicopter to drop three feet are clearly visible.
When the Playboy chopper takes off with the two men holding on you can see a safety wire holding the man who partially drops when the pants of the other man partially give way.
There are no waterways linking the Central Coast (where the only surfable beaches in South Vietnam are situated) with Cambodia.
When the Kilgore character is first introduced getting off a chopper you can see a reflection of a boom mic in his glasses.
When Captain Willard first meets Colonel Kilgore, they exchange salutes while they are still in a combat zone. It is usually military protocol not to salute in a combat zone. Saluting would show a possible sniper who the commanding officer is. (e.g. in Forrest Gump (1994) Lt. Dan correctly instructed Gump and Bubba not to salute him in the field.)
When Willard is looking through the dossier at the times that Kurtz was denied a transfer to Special Forces ("jump school"), the reason for disapproval is written: "The Army feels, all maters of age and fitness aside..."; "matters" is misspelled.
In the letter of appreciation to Kurtz re the Cobra fly-by, it says "formation of Cobra's". The plural of Cobra is Cobras - no apostrophe.
When Bill Kilgore asks about the 6 foot peak, he asks Mike about the point. Earlier, Kilgore introduces Lance Johnson to Johnny from Malibu and Mike from San Diego and Johnny is really the one he asks, not Mike.
When Kilgore wants the tree-line bombed with napalm to the stone age, he asks for "Dove Four" and the pilots respond with "Dove One-Three", and "Dove Four" is never referred to again.