Continuity mistake: When Joker is talking to the colonel about his peace badge, it is there at the beginning of the conversation, but then disappears when Joker turns his back to the camera. It then reappears in the next scene when he is walking along with Rafterman.
Continuity mistake: As the men get out of bed to attack Pyle, a close-up of Cowboy shows him looking to Snowball. Both are in bottom bunks. Between them we see a pair of legs lower and hang from a top bunk. The shot changes to a more distant angle and the legs repeat the motion. (00:28:50)
Continuity mistake: When Joker goes to see Cowboy and the squad are sitting in the temple, the dead Vietnamese's face can be seen without the hat covering it. When the photo is taken by Rafterman, his hat appears and is removed.
Continuity mistake: While Hartman is addressing the privates, who sit on the bleachers, the sky behind keeps swapping from dark grey to sunny, back and forth depending on the angle.
Continuity mistake: After Hartman punches Joker, the scene shifts to Joker's point of view with Hartman pointing his finger directly in Joker's face while berating him. After the scene changes to a distant shot, Hartman is pointing behind Joker's head.
Continuity mistake: When the squad is first ambushed they take cover around the corner of a building. Around the corner the window is boarded up. The next shot the window is unblocked and wide open and it enables the sniper to shoot Cowboy.
Continuity mistake: Just before the jelly doughnut scene, as Hartman is walking up the aisle, he is in front of Joker's locker, about to reach Pyle's locker. A moment later he comes to Joker's locker, before he gets to Pyle's.
Continuity mistake: When Hartman slaps Joker, Joker's head is turned sideways by the slap. A moment later, he is looking straight down.
Continuity mistake: When Hartman is showing the doughnut to the Privates, it changes looks depending on the shot: smooth and sugar coated, or wrinkled with barely any sugar.
Continuity mistake: During the scene where the Joker moves into the building to kill the sniper, the sniper sees him and starts shooting at the pillar he is behind. During this shot, large chunks of the pillar fall away, but in the next shot, when the sniper gets shot, the pillar is intact.
Continuity mistake: The shape of the beam of light coming from Joker's torch, after he enters the bathroom where Pyle kills himself, is different from the shape of the beam before he enters.
Answer: It was Gustav Hasford's idea. It happened in the original book that the story is based on, "The Short Timers."
Captain Defenestrator