Continuity mistake: When the meteorite falls on Munson's bed the glasses and papers on the blankets keep changing positions between angles.
Revealing mistake: In the plane, when the eclipse occurs, the inside of the plane including Flash and Dale's faces turns to a bright fakish red; an impossible situation that gives away the lighting filter used to dramatize the eclipse effect.
Continuity mistake: The first time we see Flash waiting to ride in the plane he has no sports bag next to him, but the next shot he does, and in the wide outside angles of his car the bag is nowhere to be seen.
Continuity mistake: When Zarkov watches Kala's corpse, the amount of black goo changes between one frame and the immediate next one. This happens BEFORE her body starts collapsing.
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.
Revealing mistake: When Flash and Vultan are watching the battle, Flash is on his bike with moving hair and all, but the distance to the shuttle never decreases, revealing he's really not moving. (01:27:35)
Revealing mistake: Flash is inside his car reading when hot hail starts to fall in front of the camera. Problem is, the shot is from inside the car, which is absurd.
Continuity mistake: When Dale escapes and fights the guards, the editing is really awful: first she knocks a guard, who later on changes positions. Then she walks away, leaves her shoes on the floor, and hides against a wall, but after a brusque cut she appears somewhere else, the shoes are 15 meters away and the guard from before lies in front. (I guess that some of the fighting in between was deleted.)
Continuity mistake: Ming kicks a silver cup into the void. When it falls, the cup becomes green coloured.
Factual error: A meteorite zooming through the atmosphere would crash on the ground at a high speed and with a really high temperature, not like a cardboard orange-painted ball thrown from a couple meters away, as it happens in the movie.
Revealing mistake: When the movie starts, hot hail starts to fall, but in the close-ups it just falls on a tiny area on the ground, in the rest of the wide angles the hail is gone, it neither falls nor is seen on the ground.
Answer: Spider.