Revealing mistake: When Indy has just climbed the stairs in the library and is leaning over the rail to look at the X below, directly behind him is one of the worst props I've ever seen - a flat fake book case. (00:29:00)
Revealing mistake: When Indy is breaking through the wall in the catacombs, and he uses his shoulder as a battering ram. You can see his head actually bounce off a piece of the rock real hard as he is going through the wall. If the rock was real, I guess Indy would have a lot to cry about that night. (00:32:00)
Suggested correction: This rock is real but very old. That's why it was easy to break.
Revealing mistake: In the catacombs of the library, Indy and Elsa are waist deep in petroleum. Indy has a torch, and if you look carefully, you will see burning pieces of the torch fall and hit the petroleum. Wouldn't this start a fire as Kazim later on sets the cavern alight with a single match? (00:34:05)
Revealing mistake: When Indy is being chased on the motorboard the guy behind tries to shoot him with a machine gun. If you watch the machine gun carefully it you will see it starts to disintegrate in the guy's hands and the barrel drops off. (00:38:45)
Revealing mistake: Just after Vogel is thrown out of the blimp, in the shot of him shouting towards it whilst it is taking off, it is apparent that the sky and blimp shown in the background behind him are a projection. (01:13:20)
Revealing mistake: The biplane sequence is obviously filmed in a studio close up. Despite the fact that they are miles high and swooping around at high speeds, neither Indy's hat, nor his Father's, blow off or even flap in the wind. (01:16:55)
Revealing mistake: When Kazim dies, his shirt is all bloody, but there are no holes in it. The bloodstains looks painted on. (01:26:30)
Revealing mistake: When Sallah rides up to the tank to help, just as Indy shouts, "Get Dad!" in the closeup and wideshot of Henry we can see that he's actually lying on protective support, and not lying directly on the moving tank treads. (01:35:40)
Revealing mistake: Just a small detail. Watch the tank roll over the hill with the German officer holding onto the top. When the tank hits the ground, the turret pops off. The German soldier (a clear prop dummy) maintains its grasp on the turret and is pulled off with it. The sheer force of the crash would have easily blown a human body off the tank. (01:36:30)
Revealing mistake: When Indy is looking out at the gorge in front of him after spelling out God's name, there's a shot where he looks at the lion's head above him. You can see him from down the corridor, and you can notice as he touches the wall, it moves, showing it is a fake wall. (01:47:15)
Revealing mistake: At the end a shadow appears on the cliff under Indy's shoe when he steps to the edge. This would not have happened if a solid but camouflaged bridge were there. (01:47:30)
Revealing mistake: The candles that adorn the wall in the Grail room do not appear to have a strong enough flame to put out the light they do that shines on the wall. In fact, it looks like there are electrical lamps just behind the candle. (01:49:20)
Revealing mistake: When Donovan takes a drink from the false grail, he turns toward the camera and you can see the screw holding the base to the stem of the cup. (01:52:15)
Revealing mistake: Just as Elsa leaps from one side of the precipice to the other as the Temple collapses, a rock rolls from right to left and hits her right in the head before bouncing off. (01:56:35)
Revealing mistake: When Indy is clinging to the side of the tank turret in the desert, to the right of the tank are tire tracks from the vehicle shooting the scene. They appear to just start at a set point. There was likely no way to hide this.
Revealing mistake: During the "What happens at 11 o'clock?" joke, Jr. counts down ("12, 11, 10!" or something like that) with his hand, matte lines surround his hand to the point where it almost disappears.
Revealing mistake: Indy and Henry go through a tunnel to avoid the Nazi planes, but one flies into the tunnel anyway. When it goes into the tunnel, it's covered with matte lines, and it's the wrong color.
Revealing mistake: After Indy jumps onto the tank from the horse there's a shot where he stands up to face the bad guy if you look at the tracks on the sand behind him, they aren't caterpillar tracks but tyre tracks. The reason is that for the close-up shots a fake tank was built on top of a car, a security measure to avoid anyone getting hurt in case they fell off.
Revealing mistake: When fire sweeps through the catacombs under the church, you can see that the "rats" are completely fake. At the far left of the screen (widescreen) you can see several fake rats just hanging on the wall and not moving at all. In the "special features" section on the DVD, Steven Spielberg admitted that the rats were fake - he couldn't bring himself to roast live ones so he could not make this scene appear realistic.
Revealing mistake: A bomb falls in front of Indy's car, creating a crater where the car falls into. Dr. Jones Sr. doesn't move forward due to the momentum of the crash, revealing he's been replaced by a dummy.
