Revealing mistake: In many of the scenes taking place in outer space, if you look closely you can see polygon borders surrounding space vehicles (X-Wings, Star Destroyers, and even the Death Star) indicating the objects being superimposed into the outer space background. [This mistake may only apply to the Blu Ray version.]
Revealing mistake: While Poe leads the aerial assault on the oscillator, in the closeups of Poe and other X-wing fighter pilots, note the cockpit windows at the pilots' left and right have identical marks and scratches in their individual X-wings. It's particularly noticeable when one closeup follows another.
Revealing mistake: When Amidala and Anakin are eating and he cuts her a piece of the fruit and "floats" it back to her, the bite appears in the fruit a split second before she actually eats it. [This appears to be fixed in rereleased versions]. (00:53:40)
Revealing mistake: In the shot where the Falcon is underneath the Star Destroyer, it is transparent and you can see the part of the Star Destroyer through it.
Revealing mistake: In the scene at the end of the very first battle, where Imperial troops have just taken control of Princess Leia's rebel ship, Darth Vader breaks the neck of the Captain Antilles and tosses his body to the wall. The "dead" Captain puts up both of his hands to avoid slamming his face into the wall. (00:05:40)
Revealing mistake: When Yoda knocks Darth Sidious backwards over his chair, you can see the stuntman's hand. Sidious's hands are old and his nails are dark around the cuticles, but the hand during the flip is perfectly healthy and a different size. (01:45:35)
Revealing mistake: When Qui-Gon, Jar-Jar, and Padme are eating at Anakin's house, Anakin's mum pours water for Qui-Gon. But when she gets to Jar-Jar, she tips the pitcher but no water comes out. (00:39:10)
Revealing mistake: After Rey lifts the rocks away from the back exit of the bunker, you can see C3P0 briefly as he bumps into the rock in front of him while exiting the cave, and the rock moves slightly. Also, the rocks that fell over the exit don't match the surrounding terrain at all while piled up as they are smooth like river rocks, but when we see them lifted up by Rey in the subsequent scene, they are rougher and look nothing like they did before (as well as being pretty lousy CGI). (02:16:47)
Revealing mistake: After Jyn has retrieved the data file containing the Death Star plans, Krennic is shown walking in a hallway with two other Death Troopers and pushes a button to open a door. The door begins to open before Krennic actually pushes the button to open it. While his hand is not seen touching the button, the sound of the button being pressed is still heard. (01:51:10)
Revealing mistake: When Chewy puts his hand on Han's shoulder at the end, Joonas Suotamo's finger is visible through the fur.