Other mistake: When Indy and Marion are sealed in the well of souls, they are completely cut off from the outside world. As such, other than the torches, it should be pitch black, but it is surprisingly well lit in there.
Revealing mistake: When Belloq's head explodes, the actor has been visibly replaced by a dummy.
Continuity mistake: After the plane takes off in the beginning, Indy sees the snake. His hands are grabbing at it, but a second later his hands are on the rim of his cockpit.
Continuity mistake: When Indy is driving the truck with the ark, a German tries to get in on the right side. Indy kicks the door open twice, and after the second time the top hinge of the door gives easily. The guy is half way dragging on the ground, holding onto the now askew door. Then in the next closeup, the door is hung correctly with the guy on it, and Indy kicks it again. The guy goes dragging again, and then he and the door fall off.
Continuity mistake: There is a shot during the truck chase scene where a Nazi falls out from the back of the truck and goes through the windshield of the car behind it. During the shot from inside the truck, we see two Nazis to the left. The one closer to the camera pushes the other one down. However, in the very next shot, we see that pushed-down Nazi immediately sitting up straight.
Continuity mistake: When the temple collapses, Satipo is crouching looking at the chaos. Indy starts to run and there's a wide angle of the passage ahead but Satipo is nowhere around. He couldn't have managed to run that distance in half a second.
Continuity mistake: From the outside, the sides of the hole to access the map room are in shadows, from the angle inside they are sunny.
Continuity mistake: During the truck chase scene, the radiator bars Indy hangs onto keep swapping back and forth from bent outwards to slightly bent with no continuity at all.
Factual error: There's absolutely no way Sallah and Indy would be able to lift that 'lid' (for lack of a better word) off the ark. That thing is solid rock and would weigh close to a metric ton - and none of them look like professional deadlifters to me.
Factual error: When Indy is attempting to steal the Ark when driving the truck, one of the soldiers shoots him in the arm. Then another German punches him repeatedly in the same arm, causing Indy great pain and injury. After suffering a wound like that there's no way he'd be able to move that arm, let alone raise it above his head. But the next day after the boat is stopped by the sub, Indy jumps into the water and swims to the sub without any problems.
Continuity mistake: When Indy stands inside the Map Room, looking at the model of the city, the rays of the sun are to his left, and they move right and down as the sun rises. But since the entry hole is behind him, that would mean that the sun would be to the right when standing outside - but it was to his left when he entered the hole.
Continuity mistake: When the temple collapses, Indy is holding the idol with his right hand against his chest, and the left hand free and arm extended. A frame later, both arms are extended and holding the idol.
Continuity mistake: When Belloq and the Germans are at the Well of the Souls, a top-down view shot when Indy yells, "Why don't you come on down here and I'll show you!" shows Belloq and a German soldier kneeling down to the left of him, also looking down into the hole. But, the side view shots show only Belloq standing near the opening.
Continuity mistake: When the Cairo Henchman pulls the knife on Marion, the blade edge changes position from down to up to down again.
Revealing mistake: During the big car chase where Indy follows the ark, he comes down a hill on a horse to get into the truck. You can tell the ground has already been disturbed by the horse from previous takes.
Revealing mistake: After the German is chopped up in the propeller and the plane explodes, you can the blasting cord exploding along the path to the explosion.
Other mistake: In the opening scene Indiana is with horses and scouts. A few minutes later he is running for his life and in a few moments he's at a waiting plane. Why does he need scouts and horses for the cave is in walking distance from the plane and how did the scouts and horses get there?
Continuity mistake: When Indy sits down in the seat of the plane look behind him, there is nobody holding a Life magazine or fitting the description of the man later shown watching him from the other seat.
Character mistake: Watch the extras playing the Cairo civilians walking around just before the big swordsman reveals himself to Indy. Several of them are just aimlessly walking back and forth as if they have no idea where to go.
Continuity mistake: During the truck chase, as Indy is fighting with the German driver, they knock over some scaffolding and a man drops down in front of the windshield. None of the workers on the scaffolding landed on the truck, much less the front of it. So, he shouldn't have been there.
