Trivia: Technically this wouldn't count as a mistake since it requires going through frame-by-frame, but there's an amusing little flub in the pod-race. When Sebulba's craft crashes, go through frame-by-frame when his one engine hits the rock formation. The rock formation actually begins to explode a frame or two before the engine strikes it. It's hard to tell it's happening when viewing the movie at normal speed, but you can catch it going frame-by-frame. Just an amusing little slip-up in the rendering.
Trivia: Darth Maul appears for only 6 minutes in the entire film.
Trivia: The name "Otoh Gunga" is never said in the film. The city is always called Gunga City or the Gungan City instead.
Trivia: Ray Park was originally going to provide Darth Maul's dialogue as well as his physical actions, but his voice was considered too squeaky. He was dubbed over in post-production by British actor Peter Serafinowicz (Shaun of the Dead, Guardians of the Galaxy).
Trivia: At least 3,000 boys auditioned for the role of Anakin Skywalker.
Trivia: Darth Maul has only 3 lines in the whole film.
Trivia: Before she was cast as Queen Amidala, Natalie Portman had never seen "Star Wars".
Trivia: George Lucas originally intended to film The Phantom Menace with HD digital cameras built by Sony and Panavision, which would have made it the first movie ever to be shot in digitally instead of with film. Unfortunately, Sony and Panavision could not build the cameras fast enough for the shoot, leaving George Lucas with traditional cameras instead. However, Lucas used the digital cameras on Attack of the Clones and Revenge of the Sith.
Chosen answer: According to "Inside the Worlds of Star Wars: Episode I" by Kristin Lund, they are "laser doors which lock into position in response to potentially lethal power outputs that occur intermittently during plasma activation process" (the fight takes place in a plasma energy processing plant). There are six laser doors in deference to an ancient Naboo legend in which Chaos is held back by six inpentrable gates. As you say though, they're really just a plot device to add dramatic tension to the duel!
Sierra1