Around the 35 minute mark of the movie, the House of Atreides arrives on Arrakis. As they exit the spaceship, Lady Jessica seems to be wearing a type of veil (a see-through textile the same colour as her attire) in front of her face. On the next shot the veil is on the back of her head, so her face is fully shown. On the shot afterwards (and up until the end of the scene) the veil is back in front of Lady Jessica's face.
2:03:20 When the ornithopter crashes in the desert, sand is clearly pushed in front of and up against the front windshield when it stops moving. When leaving the machine the cockpit and front windshield is shown to be above sand.
The sand falls off the window after it stops moving.
The sand falls off the window after it stops moving.
A Crysknife may never be sheathed unless it has drawn blood. This is evident near the end of the film, when the entire tribe bloods their knives. However, in the scene where Jessica confronts Shadout Mapes, Mapes fails to blood her knife.
Despite several mentions of the intensity of the sun on Arrakis, no character ever wears any eye protection.
In the middle of the movie, when Dr. Yueh brings a tray and drink in for Paul, there is one white pill on the tray. After he leaves, Paul is looking at the tray and there are two pills (1:15:56 mark).
This is not an error. The tray with two pills is in the room with Duke and Jessica.
This is not an error. The tray with two pills is in the room with Duke and Jessica.
When Paul is learning about Arrakis from the projector device, it describes the sandworms' length in meters, but the roots of the trees are in feet. The other instances of length in the film are in meters. Using both metric and non-metric measurements is by no means a mistake.
Duke Leto wears the signet ring on his middle finger. When Paul puts it on in the desert, it fits snugly on his index finger. For a "skinny" boy of 15, his father's ring would fit loosely on all of his fingers. It is well possible a boy has fingers of similar dimensions like his father's, no matter his stature.
Some time after they have arrived on Arrakis, Duke Leto tells Gurney to secure the spaceport and the spice mining operation. Surely Leto would have planned this well in advance for immediate action on reaching Arrakis? Yet Leto could still demand this to double check if all possible care has been taken.
There is some controversy as to how some of the important names are mispronounced: Arrakis, Harkonnen, Atreides, Bene Gesserit, Fremen, Kwisatz Haderach, etc. Correct pronunciation is and will always be a matter of discussion, especially when the names were just made up for a work of fiction.
When Duncan closes the supposedly heavy blast door, Paul hammers his fists onto the closed door but you clearly see the door moving under his fists, revealing it to be a light prop instead.
At around 1 hour and 4 minutes when the helicopter piloted by Duke Leto is about to land in the desert next to the carrier if you look closely from the exterior shot there is nobody actually inside the aircraft.
Although it is established that strikes have to be slow in order to penetrate a shield, there are several instances throughout the movie where fighters deliver fast blows, and yet they apparently penetrate opponent's shield, as indicated by the shield's red glow - for instance during the Harkonnen attack on Arakis and when Duncan fights Sardaukar in the research station.
At 41:23, a Fremen can be seen standing beside Mapes that has normal coloured eyes.
Kynes leads Paul, Jessica and Duncan into a place she describes as an old water reclamation facility that was abandoned when spice was discovered. This was not in the book and, from what is shown, makes no sense. Spice had been discovered some 15,000 years before this but there is no sign of weathering on the entrance, nor any other sign of wear.
The Sardaukar Bashar is clearly speaking the English dialogue shown in the subtitles - having later been dubbed over with an alien language.
When Piter de Vries is talking to the Sardaukar and they're both walking away from the camera, if you look closely the audio is Piter de Vries talking but the video is the Sardaukar talking.
The thopter Paul and mother are taken into the desert to be left after the coup is disabled remotely by someone yet Duncans isn't (he stole one to go pick up Paul and mother and is chased).
At the ecological testing station, Duncan goes outside the heavy blast door to fight the Sardaukar. Paul cannot open the door from the inside, and Liet Kynes establishes that "he's locked the door". However, the Sardaukar are also unable to unlock the door from the outside, and resort to using a laser cutter instead. If it weren't for the secret exit - which Duncan could not have known about - this door would have permanently trapped Paul, Jessica and Liet inside.
When the imperial delegation is disembarking from their spaceship, one can clearly see Reverend Mother Mohiam, played by Charlotte Rampling, walking behind the Herald of the Change. The Bene Gesserit sister is portrayed by another actress for the remainder of the scene.