Finn and Rose crash right in front of the battering ram cannon, which is shown to be heavily guarded. The enemy forces are under a "no prisoners" order. How were the heroes able to traverse the great distance back the mine's entrance without being attacked? Because Kylo Ren issued an order to have all guns fire on Luke Skywalker, therefore the enemy's attention was divided. Furthermore, it is shown that there is a trench they could take refuge in, which other soldiers are shown using.
When Finn is trying to board the escape pod, he places his bag outside of the pod. When Rose stuns him into the pod, his bag is inside.
In the opening sequence the bombers are going to throw bombs on an enemy ship. Since they are in space this won't work. Bombs don't fall down in space. They would need some kind of fire device to fire them down. Every ship, on both sides, has a device for creating artificial gravity ; which would push the bombs "down" through the bomber, and pull them "down" onto the target. In addition, it's possible the bombs have some kind of magnetic properties that would attract them to their target.
When Luke was being shot at by the AT-M6 walkers on Crait, the salt planet, the ground was blasted and scorched. When Kylo Ren shows up to kill Luke, the ground is back to normal.
At the beginning of the film during the bombing sequence, a character is seen inside her ship with the doors open to allow the bombs to be dropped out of the ship. She does not have any kind of oxygen mask or supply, despite this sequence being set in space. However, all through the Star Wars films, there are openings into space that do not affect a ship's atmosphere. We see this in a New Hope in the Death Star hangar bays and in The Force Awakens when Poe and Finn steal the TIE Fighter. A thin magnetic shield is used to allow solid matter, but not gasses, to pass through it.
In the first shot of the scene where Luke talks to R2D2 on the Millennium Falcon, R2D2's head turns towards Luke. In the next reverse shot it is still facing away, then turns around again in the next shot.
On the way toward the opening bombing run, Poe's helmet mic is extended straight out. In mid-sentence, the camera cuts to the opposite side of his face and the the mic has been re-positioned 90-degrees now properly located under his chin.
The second time Snoke and Kylo Ren meet in the red room, you can see two black-clothed technicians in the background. Although the door is always in the shot and they are not seen leaving, they suddenly disappear.
During the slow-mo chase, the rebels lost 2 or 3 support ships that ran out of fuel. It is established that the fuel for sub-light engines vs light-speed engines is separate. So why didn't they send all the support ships at the star destroyers at light speed to destroy them. The last person on board was going to die anyhow. Or why didn't the last capital ship head to the same planet to cover the shuttle retreat, there by lending cover to the shuttles? Clarification: The crews of the Ninka and the medical support ship are shown being evacuated to the Raddus before they run out of fuel, leaving them empty by the time they are destroyed. Other Star Wars media has established that jumping to hyperspace through a solid object is incredibly dangerous to any object in the vicinity, including friendly ships, due to hyper-accelerated shrapnel and the complex physics of hyperspace. Because Holdo had a plan to stealthily land on the planet Crait, which she had presumably communicated to other officers, there was at the time no need to try such a potentially disastrous maneuver, Holdo only took such a risk when the threat of total annihilation was imminent. The evacuation shuttles were already far away from the Raddus when the First Order opened fire on them, making it impossible for the Raddus - a larger, less maneuverable ship with virtually no fuel left - to have reached the shuttles before they were wiped out.
The rebels cannot jump to light speed because the First Order can track them, but the the First Order cannot catch up to them, they can only keep pace. But, it would be a simple matter for the First Order to have a couple ships go to light speed a short distance and immediately return just ahead of the rebels. The First Order could easily and quickly destroy the Rebels with this simple tactic.
If the topsoil of the planet Crait is disturbed, the white sand reveals the red, salty material. When Finn and Rose arrive to the planet, they drag on the ground in the First Order Transport Shuttle before entering through the gate. In a later shot of the gate, the ground appears white and undisturbed.
When Rey wants to hear the real truth from Luke of what has happened to Kylo and him you can see the rain pouring down. But when Rey leaves Luke's planet one shot later, it is not raining anymore and Luke and his clothes have become dry in just a few seconds. However, we know that more than a few seconds has passed because we know it takes a while to climb down to the Falcon and we also know that Rey took the Ancient Jedi texts with her.
At the end of The Force Awakens, when Rey meets Luke Skywalker for the first time, Luke's prosthetic hand is clearly exposed as he lowers his hood. However, when this scene is repeated at the beginning of The Last Jedi, Luke's prosthetic hand is covered up by a glove.
On the Island when Rey falls into the dark hole, she is underwater, but right afterward as she is walking and duplicated, her hair is wet but her clothing is dry.
Close-ups of Leia's hands show longer, manicured nails, immediately followed by unmanicured, ragged, much shorter nails. (When Poe reaches out to her, and when Luke gives her the dice, among other instances.)
Rian Johnson moved Kylo Ren's scar from the original position from the previous movie. The original wound went through the bridge of his nose, after Rey sliced his face in the climax of The Force Awakens. The problem with the new position: That scar is from a lightsaber cut, so he shouldn't have an uninjured right eye.
Princess Leia is so powerful with the force that she can fly through space like Superman, yet when the rebels are trapped they must rely on Rey's ability to remove the rocks even though Leia is with them. Clarification: While The Empire Strikes Back established that the weight of the object being moved is irrelevant to use of the Force, it has also established that the perceived weight of objects creates a psychological barrier to anyone untrained in use of the Force. The number of objects and the ability to see an object does have an impact on the ease with which the Force can be used to move things. Moving one object one direction in a weightless, frictionless environment is a relatively rudimentary use of the Force, while simultaneously controlling the movement of several dozen multi-ton objects, some of which aren't visible to the force-user in question is drastically more difficult. Also, one instance instinctive use of the Force under extreme physical duress is not the same as continuous, willful use of the Force.
In one of the first scenes Finn is talking to Admiral Ackbar and they're facing the window, while in the next cut Admiral Ackbar is facing another side.
When the Rebel ship runs out of fuel it rapidly slows down and its stern starts to tilt down as if its falling due to gravitational pull. This would not happen in space as there is no gravity and there were no large objects in the vicinity to create a gravity well. Plus in the vacuum of space an object would continue to travel at a constant velocity until acted on by another force or object, so when a ship in space runs out of fuel it wouldn't just suddenly come to a stop as there is no atmosphere in space to cause friction and create drag. Without fuel the ship actually would of been incapable of stopping or even slowing down in its own.
When Finn is continuing his attack on the Cannon after Poe has called for everyone to break off, Rose is yelling at him to stop and keeps looking to her right at him meaning she should have been on his LEFT side. However when she knocks him out of the cannon's path, she comes flying in from the RIGHT side of Finn meaning she should have been looking LEFT at him as he was first attacking the cannon.
When Kylo Ren fights Luke Skywalker, his hold on the lightsaber switches from backhand to normal and backhand again between cuts.
At some point, Rey cries and tears are running down her face. The line of her left tear disappears and reappears between the shots.
When the fathiers stampede out the stable, a guard rushes into the corner of the room near a pipe. In the next shot the guard is no longer there.
It is stated that Snoke turned Kylo Ren to the dark side while he learned at Luke's Jedi academy (probably through the Force visions Snoke later uses to lure Rey to his ship). Snoke was clearly a threat back then, being a dark side Force user, yet there is no mention about any attempt to stop him previously. Clarification: It is established in Star Wars canon that powerful Dark Side users can use the Force to obscure their presence and their actions from other Force-users.
When Kylo Ren kills the last red guard, the right hand of the guard opens. In the next shot, his right hand is a closed fist again.