When Toht grabs the red-hot medallion, his fingers are burned. Later in the movie, the burns on are all squarely in the center of his palm, and upside down compared to the position in which he palmed the medallion.
The staff is supposed to be 60 inches tall (6 kadams = 72 inches, minus 1 kadam). The pole that Indy inserts into the hole in the map room towers over his head, indicating (incorrectly) that Indy is less than five feet tall. The laserdisc edition disproves any claim that he's standing on a lower step.
When Indy and Marion exit the Well of Souls, an unidentified man is clearly seen lying against the rock face but is missing a few moments later during a medium shot that shows the same exit - the wheels of the "Flying Wing" are in the foreground. (A deleted fight scene shows Indy knocking out the man after escaping from the Well of Souls.)
The students in Indy's lecture hall change positions in various shots. The student with the apple, seen coming down the far aisle when the lecture ends, is clearly sitting in the middle of the front row earlier in the scene. The girl who has written on her eyelids is in the middle of the room when Indy first sees her but in the row by the windows later.
During the gunfight in Marion's bar, when Indiana ducks behind a corner, it appears that the type of pistol he is shooting changes with every cut. This is because one shot of Indy shooting the semi-auto appears out of sequence. After his revolver is out of ammo and he reaches for his holster, the semi-auto reappears and Indy keeps it for the rest of the scene. Evidently the semi-auto is his backup weapon; it appears later on the Bantu Wind.
For the headstone crystal to use the sun's beams to properly show the location of the Well of the Souls in the map room, it's not just enough to hold it in "a certain place at a certain time of day." It also has to be the correct time of year, as the sun's position in the sky changes depending on the time of year. Indy never seems to take this into account.
The stone cover over the ark would have weighed many hundreds of pounds, far too heavy for just Indy and Sallah.
In 1936, Egypt was not under British rule but there was a British military presence, primarily to guard the Suez Canal. It would've been impossible for German troops to operate there without the express permission of the Egyptian government or indeed the British government, e. g. to force Egyptians to work on the excavation site. For the same reason, there was no need for the US government to send Indy to stop the Nazis' search for the Ark. Simply asking their 'cousins' to end the excavation would've done the trick.
Though many snakes are able to live several months without eating, the amount of snakes in the temple is too big considering there is no food for them.
In the beginning of the film, the city of Tanis in Egypt is described as having been destroyed in a sandstorm and recently discovered by the Nazis. In reality, the city was probably abandoned when its water supply was silted in. Archaeological digs had been conducted at the site beginning in the 1800s, so the location of Tanis was well-known within the archaeology community in 1936.
The Golden Gate Bridge is shown; which was not completed until May, 1937, a year after the movie takes place. The Bridge itself began construction in 1933 (three years prior to the movie date), but not open to the driving public until April 1937, so it is easily feasible that the bridge could appear close to completion from a distance (as shown in the shot) even though it wasn't finished yet.
Toht would need more than the imprint in his hand to replicate an approximate of the amulet. He would need to know the dimensions and properties of the crystal, including the cuttings on the surface, otherwise it would not refract and focus a beam of sunlight on exactly the right place (assuming he had the correct length of the staff). Since they were digging in the wrong spot anyway, having an incorrect approximate of the amulet would further give them an incorrect location.
There are several Nazi officers seen smoking. Smoking was discouraged in Nazi Germany. However, it wasn't until 1939 that the German Wehrmacht and SS restricted officers from smoking while on duty. The film takes place in 1936, when smoking was still permitted.
If the idol is made of pure gold and is solid ( it would weigh about twice the same volume of lead and ) Indy would not be able to carry it so easily. It would also have consumed far more of a precious resource than necessary. Indy's difficulty was estimating how hollow it was, based on his knowledge of similar artifacts ; but he overestimated the weight, the plinth sank, and the boulder fell down.
In the Cairo diner, Belloq refers to a watch as "worthless, $10 from a local vendor." However, while $10 in 1936 had the spending power of $164 in 2012, Belloq was comparing it to ancient artifacts worth millions.
Immediately after the truck chase, Indy pulls into a market square and the peasants help him thwart the Nazis. In this scene, the character of Toht, sitting in the passenger seat of a Mercedes, can be seen in the wide shot played by the actor, Ronald Lacey. But in close-up, it appears as if his hat is just propped up on top of his coat as though the actor was not available, and no stand-in could be found; so they just propped his costume up in the seat and hoped nobody would notice.
German soldiers fall from the truck (which is traveling forward at 40 mph) and roll backward - in violation of physics. When you jump from a moving vehicle you actually roll in the direction the vehicle was moving.
During the desert truck chase, Indy pushes a Nazi Jeep off the side of the mountain. However, every shot immediately before and after that indicates that Indy is driving on level ground, with plenty of road on either side of him.
When Indy and Marion push the large heavy stone block away to escape from the pit, you can see the shadow of it bouncing weightlessly on the ground below.
Ronald Lacey shaved the top of his head to play Toht. In one scene Toht removes his hat to wipe sweat from his supposedly bald pate, but stubble showing the actor's real hairline can be seen.
During the montage of the submarine traveling to the Nazi base, the captain is seen looking through the periscope. If the submarine had submerged to periscope depth, Indy, riding outside on the sub's bridge, would have drowned.
It been stated by Archeologists that although there has been some booby traps found on excavations and other archaeological sights. Most booby traps were not that intricate but rather more crude in design. However most booby traps were not dangerous due over the amount decay that has happened over the years.
As Indy and Marian enter the Cairo marketplace, after the monkey returns to the eye-patched spy, an unattended shovel in a pile of sand inexplicably falls over.
When Indy arrives at the cargo ship's bridge and sees the U-boat, the German boarding party is seen paddling their skiff towards the ship. Indy runs off to find Marion, but by the time he gets to their cabin, the soldiers have already boarded the ship, found the cabin, and taken her prisoner in just a few seconds time.
When the monkey first appears, it jumps on Marion's shoulders and starts grabbing her hair, cheeks, etc and is a bit too excited, almost angry. You can see that Karen Allen repeatedly looks at a point high above behind the camera. Presumably she's looking at director Steven Spielberg, to see whether he wants to cut because of the monkey's overexcited manner.
In the flying scenes, the map lists several countries by their modern names instead of their 1936 names. Siam did not become Thailand until 1939. Transjordan did not become Jordan until 1949.
There is a globe on the desk in the classroom. The globe depicts various countries of Africa that didn't exist in 1936.
The Afrika Korps didn't exist until 1941.
When Indy ambushes Nazis in the mountain pass on the island, he is uses what it is a modified Chinese Type 56 copy of the RPG-2 - Soviet-made shoulder-fired rocket launcher. Anti-tank rocket launchers weren't even being developed at the story's time line of 1936, and nobody came with such idea at that time (there was no need for anti-tank rocket launchers with HEAT shaped charge warheads against relatively weakly armoured tanks from interwar period).
The uniforms worn by the German soldiers are the tropical models, intended for use by the Deutsches Afrika Korps (DAK), and not introduced until 1940. In 1936, they would have worn either the standard wool uniforms, or, more likely given the hot weather, model 33 cotton work uniforms.
In the car chase scene, when Indiana pushes a car off the road into the trees, the driver curses in German. However, his mouth forms the English form of the word.
When the German officer tells Gobler that he wants "plenty of protection" for the Ark, we hear Gobler answer "Jawohl, Herr Oberst!" but his lips don't move.
After Indy and Sallah have discovered the Ark within the Well of the Souls, they pack it in a crate and it is hauled out by the workers. As it is being lifted up, Indy says, "Alright, take it up. Easy!" yet his lips don't move.
After the group of kids save Indy from the bar, grown-up characters are talking in front of an open truck. While Sala speaks, there clearly is a boy playing a flute. But no flute sounds can be heard.
When Indy is holding onto the front of the truck with the wheel between his legs after being thrown out of the window, a shot of his back reveals the small wooden seat he is sitting on.
When Indy and the monkey are getting drunk after the truck
carrying Marion has been blown up, a young man in a T-shirt and jeans walks past in the background on the left side of the screen (all the other people are wearing robes).
After Indy kills the driver of the truck in Cairo and it explodes, you can see a camera angled directly across from the burning truck.
During the shot in the plane cockpit where Marion shouts "Indy!", you can see on the right side of the window, the reflections of various crew members and their vehicles of which would not be in the year 1936.
Why does the floor move? When Indy throws the torch down the 'Well Of Souls' that reveals the snakes, obvious fake snakes (screen left) can be seen being pushed (not slithering) into the scene along with the many real snakes.
The cobra that Indy lands in front of in the Well of the Souls is a monocled cobra, noted for its distinct pattern on the back of its hood. This snake is native to South and Southeast Asia, and would not be found in Egypt. There is an Egyptian cobra, but it looks quite different.
Several of the snakes used in the Well of the Souls scene are Burmese pythons and Reticulated pythons - neither of which are native to any part of Africa.
The tarantulas at the beginning of the movie are Mexican Red-Knees that are native to Mexico only.
At the 23 minute mark, a background image of the Golden Gate Bridge is seen as the Pan America seaplane is theoretically taking off from San Francisco to go west to Hawaii. Except that the GG Bridge image shows the seaplane going EAST as the arch under the bridge roadbed protecting Fort Point is seen to the right, which marks the south end of the bridge.
Also, we know that the flight's earliest date is November 30th, 1936 due to the LIFE magazine that Toht is carrying. If that is the case, the Golden Gate Bridge image is incorrect as the northern and southern sections of the roadbed had not yet been joined. If the flight is in January of 1937 (with Toht carrying a 2 month old copy of LIFE - not likely for someone trying to be inconspicuous with such a famous magazine), then the GG Bridge image would be correct as the roadbed(s) were linked up at this time and only needed another 4 months of reinforcement and laying the asphalt to complete the bridge.
Also, we know that the flight's earliest date is November 30th, 1936 due to the LIFE magazine that Toht is carrying. If that is the case, the Golden Gate Bridge image is incorrect as the northern and southern sections of the roadbed had not yet been joined. If the flight is in January of 1937 (with Toht carrying a 2 month old copy of LIFE - not likely for someone trying to be inconspicuous with such a famous magazine), then the GG Bridge image would be correct as the roadbed(s) were linked up at this time and only needed another 4 months of reinforcement and laying the asphalt to complete the bridge.
The ark is opened on an island in the Aegean Sea that, on approach, is clearly composed of igneous rock, which is consistent with the geology of the area. However, upon entering the island, the interior features sandstone canyons, which is geologically improbable for the area and impossible given the rocks shown in the previous view of the island.
The flying wing doesn't have any storage space to carry the ark in its crate and there isn't a way to carry it underneath it either.
The old man interpreting the headpiece says the staff is six kadams high. Indy says that is roughly 72 inches. That makes one kadam equal to one foot (in reality, one kadam is closer to 10 inches). The old man then says take back one kadam, making the prescribed height of the staff five feet. When Indy enters the Map Room, he uses a staff that towers over his head, well over five feet.
There are many flaws with the U-boat sequence. The class of boat is wrong - U-26 was a Type IA, but that shown is a Type VIIC (this is because the film reused the replica of U-96 from Das Boot (1981)). Neither the Type IA nor VIIC - nor any of the principal classes - would have been capable of carrying the Ark, due to limited storage space and access hatches that were too small. The Captain clearly orders the U-boat to dive ("Tauchen"); however, a lack of a constant air supply, much reduced speed and limited capacity for the electric motor batteries meant that U-boats only submerged for defense, attack or in heavy weather - none of these apply here. Nor did U-boats sound a 'diving' klaxon. A cut scene shows Indy hiding aboard the boat by clinging to the periscope. However, as explained the boat would not in reality have dived, and even when it did it would not have run at a sufficiently shallow 'periscope depth' the whole time. On the surface, at least four men would have been on watch at all times. Even if he could have remained hidden while the submarine remained above water he would have died from exposure. The trip would have taken many days to reach its target and he would have died of thirst long before then. Thus, however Indy tried to smuggle himself aboard the boat, he would have either been spotted or drowned.
When trapped in the Well of Souls, Jones clubs a large 30ft stone statue and rocks it back and forth in an attempt to escape. In reality, this statue would have weighed many tons and it would be impossible for one single human to topple it using only his body. If this were the case, earthquakes would have caused it to fall down thousands of years ago.
In the beginning Indy says he has no idea where Abner (or Marion) are but the Nazi cable states he is in the United States and possibly has the headpiece/medallion. Yet Indy gets on a plane and flies to Tibet/Nepal without attempting to locate Abner Ravenwood in the States. He immediately finds Marion in a mountain top bar that she owns. She tells him Abner is dead and Indy asks her for the headpiece.
Marcus Brody mentions that "The Bible speaks of the Ark leveling mountains and laying waste to entire regions. An army which carries the Ark before it... is invincible." Nowhere in the Bible does it say the Ark itself has any power whatsoever, let alone making a human army invincible. If anything, in 1 Samuel 4, it tells how the Hebrews brought the Ark into battle with them.
The trained German soldiers hold the MP40s incorrectly, holding the magazine instead of the forward stock. Surprisingly, the untrained street thug holds the weapon correctly.
Before the airplane fight, Gobler addresses Dietrich in German as "Herr Major", indicating Dietrich's rank equivalent to Major. After the airplane fight, his voice has changed (see above unsynchronized goof), and he changes Dietrich's rank to "Oberst" (equivalent to Colonel). This also matches his rank insignia which marks him as an Oberst.
While Belloq and Marion are drinking in the tent, Belloq says the alcohol is "[his] family label". In the previous shot, the writing on the bottle is in Arabic.
During Indy's lecture to his students on the Neolithic, Dr. Jones talks about a "cist", which is a chest-shaped burial. Dr. Jones pronounces the word "cist" wrong - Archaeologists pronounce "cist" with a hard "k" sound at the beginning, whereas Dr. Jones pronounces it like "cyst" with a soft "s" sound. A genuine Archaeologist who knew about the Neolithic would not make this mistake.