Continuity mistake: When the queen is being escorted by some droids after she has been captured, there is a shot of Obi-Wan and Qui-Gon watching the queen from a balcony. The shot shows the queen passing by them. Qui-Gon then takes a few steps and is somehow very far ahead of the queen and the droids. They didn't use the force run because Jar-Jar was right up with them. (00:21:30)
Continuity mistake: In the shot where Qui-Gon introduces himself to Anakin's mother, Jar Jar, Padmé, R2-D2 and Anakin are standing half a metre to the left (your right) of where they were standing in the previous shot. (00:36:50)
Continuity mistake: When Jar-Jar is helping repair Anakin's podracer, he loses his tool in the motor. When he tries to take it, it is suddenly stuck in the compressor, some centimetres ahead and over.
Continuity mistake: Just before the podrace Qui-Gon talks to Shmi on the platform. After the conversation, they walk towards the camera. Pay attention to the background, it's the same as the previous shot even though Qui-gon and the others are walking in the other direction.
Continuity mistake: When Captain Tarpals gives Jar Jar a zap with his power pole, the fish and the appearance, size and position of some of the bubble building outside the membrane change between shots. (01:14:05)
Continuity mistake: When Qui-Gon and Watto are talking in the hangar before the Podrace, Qui-Gon says "You don't think the boy can win?". You can see Watto's waist strap disappear into him. (00:52:30)
Continuity mistake: When Anakin is packing his backpack while speaking to C3PO, there is a toy on his bed like a Naboo fighter. In the next shot, it changes place and orientation. (01:14:30)
Continuity mistake: When Padme is cleaning R2D2 and chatting to Jar-Jar, the film's reversed in the final shot of Natalie Portman smiling. The easiest way to notice it is that when we're looking at R2D2, normally his lens is to the right of a blue/red light, but in the final shot the lens is now to the left of that light. (00:27:57)
Continuity mistake: When Obi Wan is fighting with Darth Maul, Maul knocks Obi Wan back into the reactor pit using the force. When they first show Maul's hand, it is his right hand that takes off the lightsaber and pushes Obi Wan back. When the camera angle changes to show Obi Wan rolling backwards into the pit, Maul's left hand is clearly shown raised.
Continuity mistake: As Obi-Wan is looking up at Darth Maul and Qui-Gon, they are fighting in the middle of the walkway. When Obi-Wan jumps up, they are at the doorway at the end of the walkway. They couldn't have reached the end of the walkway that quickly. (01:51:50)
Continuity mistake: After Darth Maul falls off the walkway, Qui-Gon jumps down after him, and there are several vertical beams behind them. In the next shot, they have suddenly moved past them, but in the following shot, they are fighting in front of the beams again. (01:51:05)
Continuity mistake: After Darth Maul sits down in his speeder, the probe droid flies past him, but in the previous shot, it was nowhere to be seen. It should have been visible, because of its position and the direction it was coming from. (01:13:35)
Continuity mistake: After Obi-Wan falls off the walkway, he manages to grab hold of the edge of another walkway, and on the floor, there's a lit strip near his hands, to his right. When Qui-Gon and Darth Maul continue the fight, there's a wideshot where Obi-Wan (still hanging from the edge of the walkway) can be seen in the lower left hand corner of the screen. His hands are now further away from the strip, and are closer to the strip on his left. (01:50:50)
Continuity mistake: When Anakin says goodbye to his mother, his shirt collar keeps moving up and down his neck between shots. The easiest way to see this is to watch his necklace, which is more covered up by his shirt in some shots than others. (01:11:45)
Continuity mistake: When Qui-Gon is fighting Darth Maul on Tatooine, Obi-Wan sits down in the cockpit of Amidala's starship. As the shot ends, his hand is up by the top of Ric Olié's (the pilot) seat. In the beginning of the next shot, his hand is down by his side, and Anakin's hand has suddenly appeared on top of the seat. (01:14:00)
Continuity mistake: In Otoh Gunga (the Gungan city), when Captain Tarpals comes to arrest Jar Jar, the background in the shots of Obi-Wan and Jar Jar doesn't match the background in the previous and following shots. (00:13:50)
Continuity mistake: When Anakin and Obi-Wan walk up to greet Palpatine on Naboo, in the wideshot, a Republic guard is passing by them. In the close-up, the guard is gone. (02:00:40)
Continuity mistake: During the Podrace, Anakin's face alternates between being dirty and being clean several times.
Continuity mistake: When Nute Gunray (the Viceroy) and Daultay Dofine are talking to TC-14, they are standing further away from each other in the wide shot than in the following close-ups. (00:03:30)
Continuity mistake: Before Anakin says goodbye to his mother, she is standing in sunlight next to the hut. As Anakin runs back, she is standing in shadow. When he reaches her, the area is covered by sunlight again. (01:11:50)
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 ★