Corrected entry: The animations (and the DVD subtitles, but the animations particularly) frequently change between the spellings 'Lancelot' and 'Launcelot'. Compare the book animation where we are first introduced to Sir Lancelot to the animation that shows 'the Tale of Sir Launcelot'.
Corrected entry: In the final scene, as the black police truck arrives, you can see a boom microphone reflected in the side of the truck. Seen on the VHS edition.
Corrected entry: When the knights are talking with Tim about the Cave of Death, Tim says that the inscription describing the location of the Grail was written by "Alther Bedwin of Reggeth," yet it's said elsewhere in the movie that the inscription was written by Joseph of Arimethea.
Corrected entry: When Sir Lancelot is running to the castle to save the prince, the same shot is shown many times so he runs up the hill, then appears at the bottom at the start of the next shot.
Corrected entry: In the scene were King Arthur fights the Black Knight, prior to Arthur's arrival the Knight is battling some unworthy adversary. When he is defeated he falls to the ground near the Black Knight's feet, but when Arthur approaches the corpse is nowhere to be seen. Even in wider shots during their fight, he's nowhere.
Corrected entry: The sequence order of each knight's tale doesn't work. Lancelot rescues Galahad before his tale begins and then we don't see Galahad again but you know that he stayed with him because it says the other knights meet up with the two after.
Corrected entry: If the Holy Hand Grenade of Antioch can blow up the killer rabbit then why couldn't Tim the Enchanter just shoot it with a flaming missile and be done?
Corrected entry: When the head knight of Ni says he must cut down the mightiest tree in the forest with a herring he produces a kipper.
Corrected entry: The Knights who say Ni are rumoured to be connected to the mock subtitles in the opening credits which advertise Sweden. In the Swedish language, "Ni" is second person plural (the equivalence of the English plural "you") and used to be the proper form for adressing people outisde your circle of family and friends. This was however abandoned during the late 1960-ies/early 1970-ies in the so-called "du-reform" ("du" being the second person singular form). According to the rumor, the joke with the knights saying "Ni" and people's negative reaction to it is a mockery of how the "ni" form was rejected by almost all Swedes, and thus no longer acceptable. Over the years the Pythons have gone back and forth between denying that the rumour is true, and confirming that it is indeed true.
Corrected entry: In the French castle scene, when the Frenchmen are exiting the castle to get the wooden rabbit, one of the Frenchmen has a hole in his armor between his legs.
Corrected entry: During the scene where Brother Maynard is reading the carving in the cave, you can clearly see a different person playing Sir Robin. Robin is normally played by Eric Idle but in just that scene it is a totally different person. (Eric Idle also played Brother Maynard. A similar thing happens in the previous scene - John Cleese played Tim The Enchanter as well as Launcelot, so the latter didn't appear in that scene).
Corrected entry: At the witch's trial, during the long pause while they are thinking of something that also floats in water (a duck), Eric Idle is desperately trying not to laugh - he even goes as far as biting the top of his sythe to cover his giggles. This is mentioned in the commentary on the DVD and once you've noticed it, you won't be able to watch the scene again without your eyes glued to poor Mr Idle.