Continuity mistake: As the boat approaches Kurtz' compound the dead body hanging from the tree on the left of the screen is motionless. Six seconds later as they get a little closer the body is twisting and swaying even though there is no wind and no person goes near it. (02:29:00)
Audio problem: As Captain Willard walks Lance away from Kilgore you hear him say, "just keep walking". If you look closely at his lips you'll see he's saying much more before that which is dubbed out. (00:50:45)
Continuity mistake: As Lance is on the top of the PBR Captain Willard says to himself, "He's close, he was real close" and they shuttle between shots of Lance and close-ups of Chief Phillips at the helm. The straw hanging down from the roof of the boat behind Chief Phillip's head is is hanging down differently in both of these shots. (02:21:05)
Continuity mistake: After the rocket attack Chief Phillips looks back and says, "Chef, Chef check out Clean. Captain, he's hit". Look closely at the blood spatter on that the piece of metal that was behind him during the attack. Later as Lance takes over the helm of the boat there's less blood dripping on it. (01:52:30)
Audio problem: We see and hear Chef rip the picture from his Playboy magazine of Miss December in half. In the next shot as he tapes it up behind Chief Phillips it's all in one piece. (01:12:05)
Continuity mistake: There's no indication that Captain Willard didn't leave for his mission immediately after having dinner with the General, being that his R&R was over. That nasty cut on his thumb is all healed without any band-aid on it by the time we see him in the next scene on the PBR. There was also a dark scab on his middle finger that was there as he smoked a cigarette in the end of the scene with the general that has also disappeared. (00:20:30)
Continuity mistake: In the scene where the Boat captain gets speared, a poor job was done with the whole thing. First, the spear that the native throws is much bigger than the one that is actually stuck in the captain. Second, the spear that is in the captain would have been too small to throw with any accuracy, let alone that distance. Third, a spear of that size would not have had enough velocity to penetrate the captain all the way through his body. (02:22:31)
Factual error: In the scenes where members of the boat crew are wearing berets, they are worn incorrectly. Both Clean and Chief Phillips have their berets with the insignia over the right eye with the rest of the beret slanting over the left ear. That is the manner in which the French armed forces wear berets. The US and British forces wear them with the insignia over the LEFT eye with the rest of the beret slanting over the RIGHT ear. Ask any Ranger or British soldier.
Continuity mistake: In a close-up after he burns the picture of his wife with his cigarette, Captain Willard says to himself, "When I was there all I could think of was getting back into the jungle". Look closely at his left cheek and note a red scratch missing from previous shots and not visible in later shots during his drunken dance. (00:05:20)
Continuity mistake: In the close-up of Chief Phillips piloting the boat up to the French plantation dock look closely at the pair of boots hanging evenly by their shoe laces over the 50 BMG that Chef is pointing towards the dock. He hasn't taken his fingers off that machine gun but when Chef gets ready to leave the boat the boot on the right is now higher than the one on the left. (01:56:10)
Continuity mistake: After Lance and Captain Willard return to the boat Chief Phillips says, "which way captain". As the captain sits on the front of the boat look closely at his tee shirt, he has something underneath resembling a large newspaper or package. When he takes his tee shirt off there's nothing under there except his dog tags. (01:47:55)
Continuity mistake: Before they swing the boat around and head to shore to meet up with Lieutenant Kilgore it's the middle of the afternoon with the sun above them. When they reach the shore in the next shot and get off the boat it's sunset. (00:24:30)
Continuity mistake: As Jerry takes a piece of roast beef from the tray we get a close-up of the captain's table setting. Just about everything has been moved from the previous shot but his bread dish and napkin are the most notable as they have both moved to the right of where they were before. (00:12:10)
Continuity mistake: As they walk on the dock at Hau Phat the storage warehouse behind the motorcycles is very well lit up. In the previous shot as they were docking these areas were bathed in a dim blue light. (01:04:30)
Revealing mistake: In the celebration scene in the Buddhist Temple, a boy asks one of the characters for money. This would be fine, except he's speaking in Filipino and the film is set in Vietnam.
Other mistake: The comment about covert missions into Laos where everyone had foreign weapons and uniforms, etc., is bull. Many, many men went into Laos, fully equipped on UH-1A choppers with American gear. The recon teams were outfitted with American gear. I haven't found anyone that could accurately estimate how many, but a lot. A friend that came back from there said they had maps, radios, uniforms, sidearms, fully equipped choppers with rocket rounds, and so many spare barrels and boxes of ammo for the 60s they could barely get off the ground with 4 crew members. No foreign anything in choppers or teams going in or out for any trip. Not saying it didn't happen somewhere during the war, but it was not something that happened in Laos from dozens of combat vets I've talked to.
Continuity mistake: The entire French plantation dinner scene is beautifully lit. It looks as though it's sunset until Hubert walks over to the window in middle of the scene. As he stands by the window we can see outside and it's not sunset but midafternoon. Then as he walks to his seat he passes back into the yellow stage lighting again which makes it look as if it's sunset. (02:08:50)
Continuity mistake: At the beach party Lieutenant Colonel Kilgore says, "bring me my Yater Spoon the eight-six". Later when Captain Willard steals this surfboard from his helicopter it's not a Yater Spoon, which has a distinctive flat tail and can be seen at www.yater.com. (00:51:25)
Deliberate mistake: Martin Sheen has a cut on his cheek that starts as a scar and becomes an open wound. (00:02:27)
Revealing mistake: A Medevac helicopter lands in the courtyard and later explodes when a Vietnamese woman throws a grenade into it. The copter that lands is not the one that explodes. The front of the helicopter that blows up is older and beat up and the window on the pilot's door does not have any green sun shade on top as the other chopper had when it landed. The one that explodes is also on a platform that collapses as it blows up. (00:44:15)
Answer: It's not any specific song; it's just the kind of generic piano music you'd hear at dinner at a high-class restaurant of the era. Think of scenes in movies, films, etc. set or made in the '50s and '60s, where the characters go to a nice dinner and there's someone at the piano playing unobtrusive music to accompany the food/conversation.