Continuity mistake: When Dale hugs Flash before his fight in the ring, the position of both of her hands is inconsistent between shots.
Continuity mistake: When Kala is shot, she falls forward. From a different angle, she remains standing upright.
Continuity mistake: When Ming is about to die, he slips away from the spike, which has parts of it covered in green blood. When Flash sees him, the spike is fully covered in green blood.
Revealing mistake: When Ming dies, one can see his real left eyebrow. The makeup covering it is missing.
Revealing mistake: Zarkov's rocket blasts through the greenhouse ceiling, but doesn't burn or scorch a single millimeter of the place.
Continuity mistake: The pilot hands Flash a People magazine to sign. When Flash sits down to autograph it, one can see it's already signed (seemingly from previous takes). Then he scribbles on the same spot again.
Continuity mistake: When the movie begins, Flash is reading a newspaper, sitting sideways, his back leaning on the door. When Dale's van arrives, he is facing straight, with the paper resting on the steering wheel. Then the shot changes to the first position and he turns sideways towards the wheel.
Continuity mistake: The egg timer in the jail is about to run out, but when Dale runs over to it and tries to turn it over, there is more sand in it than before.
Revealing mistake: Just after Klytus has his sticky curtain call, and King Vultan orders the evacuation of the Sky City, watch for the wide shot with the fleeing Hawkmen superimposed in the background. As Vultan tells our heroes he and his men have too much to carry to give them a ride, watch his entire multitude of brave fleeing Hawkmen suddenly disappear one frame before the next shot cuts in.
Continuity mistake: When Flash is restrained in Ming's dungeon, he has a spiked headpiece on, preventing him from seeing. The spikes on this headpiece change position from shot to shot during this sequence in relation to his tied-up arms - i.e. the headpiece keeps being turned, and then is back in position again depending on the shot.
Continuity mistake: When Flash, Dale and Zarkov first land on Mongo, the shots from inside the ship show Ming's guards walking right up to the ship's window and looking inside. When it then cuts to an outside shot, the guards are much further away.
Continuity mistake: When the Barron and Flash are fighting with the whips, they hit each other and cut each other on the arms, hands and face, but in the scenes after the fight, neither one of them have so much as a scar where they were once cut.
Continuity mistake: When Ming is impaled on the nose spike of the Imperial craft, the spike is perfectly horizontal. When he eases himself off the spike, it is pointing downwards much more.
Factual error: A meteorite falls onto Munson's bed, setting fire to it. He covers it up with blankets. But the meteorite is still red hot and would surely burn through, and set fire to his bed again.
Other mistake: When Hans Zarkov is having his mind scanned we see tons of images flash by. The one for "Space scientist fired" is several paragraphs long but only the first one was about Hans. The rest is about a leash law in Wellesley, MA.
Continuity mistake: While Dale is watching the destruction of the palace, her head is either tilted or looking straight, depending on the angle.
Continuity mistake: In Arboria, while Aura kisses Barin she says "I brought you a present", then her left arm swaps from being up to down between angles.
Revealing mistake: When the spaceship flies, Zarkov keeps warning about the g-force and Dale and himself suffer it, yet when he tells Flash to step on a pedal, Flash manages to lift his foot and do everything effortlessly, g-force magically gone.
Continuity mistake: When Flash is seated inside the gas chamber and a hood is being put over his head, he swaps from facing to the left to straight between one frame and the other.
Revealing mistake: While Flash and Barin are fighting with the whips, Flash takes a swipe at Barin with the whip and hits him in the face. Before the whip strikes Barin, you can see the red blood on his face, we then hear the crack of the whip, Barin yanks his head back as if he had been hit and then comes back into frame smearing the red blood.
Answer: Since one meaning of "bore" has to due with digging tunnels and they are used in the torture scene, one can assume that they are worms that eat holes into your flesh.