Errori geografici: Several hills appear outside Johnny Rico's house in Buenos Aires. In real life, Buenos Aires does not have any elevations in sight from any part of the city.
Microfono visibile: After they capture the brain bug, the shadow of a boom mike is visible on Jenkins' trench coat.
Incorrectly regarded as goofs: When Rasczak is teaching the high school class, his arm appeared to some to be amputated above the elbow (thus making some later scenes inaccurate), but in fact it is not; it's below.
Incorrectly regarded as goofs: The odds of a ship physically running into an asteroid launched from Klendathu to Earth are literally astronomical. However, there's no strong evidence it really was launched from Klendathu; this is an assumption the humans make, and its very absurdity (and the early death of the only reporter to question it) is part of the point.
Continuity: The green gore on Flores' helmet is missing the next time the film cuts back to her after the initial spattering scene; in subsequent shots it is there but the amount varies.
Personale o equipaggiamento visibile: When Rasczak's mobile infantry troop are on their way to investigate the distress call on Planet P, Rico is scanning the tops of the canyon walls with binoculars. When he almost sees the winged Arachnid, there are rocks falling. A hand can be seen lobbing one of the rocks over the wall.
Factual errors: The asteroid generates a gravity field strong enough to tip the surface of some liquid in a glass by 45 degrees - yet the glass itself remains rock steady instead of sliding forward. Perhaps it had a particularly sticky base.
Varie: During training when the drill instructor throws the knife at Ace, blood appears on Ace's hand before the knife hits.
Revealing mistakes: The "Bug Planet" was filmed at Hell's Half Acre, Wyoming. In the widescreen edition, watch for the "flying recon bug" (a sort of dragonfly), and watch the upper right corner of the screen for a brief view of the Wyoming grasslands and the highway beyond.
Continuity: In the shower scene, Johnny's butt is already red before it is smacked.
Continuity: During the punishment, the leather piece Rico is biting down on changes positions between shots.
Personale o equipaggiamento visibile: When a bug falls on a collection of barrels the wires pulling them are briefly visible.
Errors made by characters (possibly deliberate errors by the filmmakers): Various characters (including Ibanez) mispronounce the surname "Ibanez".
Varie: The top of Pvt. Ace Levy's swimming trunks are visible during the shower scene.
Revealing mistakes: During the football game, Rico runs up a ramp before flipping over the opposing players. However, in the long shot, no ramp is visible.
Personale o equipaggiamento visibile: In the second scene where the MI are going to kill the bug that has just killed the reporter. Just before the first fires on the bug, the shadow of the camera can be seen on his leg.
Continuity: While defending the fort, Rico and Ace, and the man next to Ace, duck for incoming hopper bugs. In the next shot, the man next to Ace is still standing.
Audio/video fuori sincrono: While at the outpost, Ltl Raczak's mouth moves, but nothing comes out just before he says, "Fire at will."
Continuity: While defending the fort, Rico removes his helmet to make a radio call. When he does this, his hair is messed up. However, before placing the helmet back on, he is seen again with perfect hair.
Audio/video fuori sincrono: When Lt. Raczak's legs are severed at the outpost defense, he tells Rico "You know what to do!" The audio doesn't match up with his mouth movements.
Revealing mistakes: When Rico and Zander are fighting, Zander pulls Rico onto a table and starts pounding him in the stomach with his elbow. The part of Rico's stomach that is being pounded is protected by a protective pad.
Continuity: A bug's leg pierces Carmen's shoulder when she is captured. After rescue by Johnny, the blood remains, but her uniform has no visible hole. She also seems noticeably unaffected by the injury, able to use her shoulder easily.
Continuity: When the tanker bug first appears it has three pairs of big legs and a number of little ones. As the scene progresses one pair of big legs disappears.
Continuity: During the Tigers vs. Giants 'Football' game, after the first shown play, there is around 2:42 left, with a time out. After the next, few seconds play, there is (on the clock) at least 4:00 left (announcer says 2:42, with a time out). Then the announcer says 40 seconds, then the game is over after another short play.
Factual errors: The asteroid destroyed by the improved planetary defenses in the first newscast stops immediately upon being hit by the missiles. In fact, the fragments should have kept moving forward.
Factual errors: At the rate the asteroid had to be moving to hit Buenos Ares, during the phone call, they would've never seen a shadow moving. Nor would they be alive to see the shadow as the pressure wave would flatten it first.
Continuity: Sergeant Zim pins Ace's hand to a wall with a knife, but when he pulls the knife out, there is no knife hole in the wall. There are two small holes, like nail holes (or they may be clots of blood), but nothing broad enough for the knife.
Factual errors: After an asteroid knocks the Roger Young's superstructure off, we see atmosphere and debris streaming out and trailing behind as it would in an atmosphere, like smoke from a train. If the ship is not accelerating, the debris should continue moving at the same speed as the ship. If the ship is accelerating, the debris should still continue to spread out.