All the Sumerian people are super-sensitive to light except the three women chosen for the sacrifice. They walk into the room of the Fire of Ishtar with their eyes wide open while the rest of the population have to shield their eyes from the light when the door is opened.
The positions of Dr. Bellamin's arms change when they are looking at the map.
Lafarge says "Dr. Bentley, do you remember the Gilgamesh tablets that George Smith found?" George Smith did not find the Gilgamesh tablets. He was the British Museum assistant that first translated the tablets in 1872. The tablets were discovered in 1839 by A.H. Layard. Later, Dr. Stuart questions the existence of a "Sumerian version of Noah's Ark." Dr. Bentley responds "Exactly. The flood has been proven to be a historical fact, why not a Sumerian version?" The Sumerian version (the story of Utnapishtim and the flood) is found in the Epic of Gilgamesh, which they spoke of earlier; therefore, it should be no surprise to Dr. Stuart. These do not appear to be very learned archaeologists.
The name of Schliemann is pronounced by the movie characters as "shlaiman" rather than "shleeman". Schliemann was famous enough in the archaeology world that professional archaeologists should be aware of how his name is pronounced.
The ancient civilization that the scientists find write in what appears to be Egyptian hieroglyphics but somehow they speak perfect English.
Three sacrificial women enter the death chamber. The four guards carrying two stretchers bring out the bodies. What happened to the third body? It's on the second stretcher alongside the second woman.
The civilization discovered by the archaeologists is supposed to be Sumerian, yet the writing on the walls of the king's and high priest's chambers are in Egyptian hieroglyphics.
When the three archaeologists are captured outside the underground city, the face of the actor that grabs Lafarge can be seen at the top of the screen, wearing dark face paint, but not wearing his mole man mask. Also, his mole-hands are clearly seen to be just gloves, as the skin of the actor's forearm is visible beneath his sleeve.
Following the avalanche on the mountainside, the archaeologists find the broken arm of a statue sticking out of the snow, which is then slowly pulled over by a black wire.
As the archaeologists descend underground (long before they reach the illuminated cavern), there is far more light than physically possible, even without use of their single flashlight.
When the archaeologists find the arm of a statue in the snowbank, it's obvious that it's not real snow since it looks like Styrofoam packing pieces.
Ishtar's symbol was an eight-pointed star, not the uneven chevron logo shown in the movie.
Ishtar is a Babylonian goddess, not a Sumerian one.
The Eye of Ishtar would not burn anyone. Sumeria in Iraq is too far north for the sun to ever shine to the bottom of a vertical shaft at noon. The northernmost latitude where the sun can stand at the zenith at noon is at the Tropic of Cancer and even then only on the summer solstice.
At the end of the film when the two scientists and Adel return to the surface world. where did they get the winter outfit for Adel when there was no other woman in the original party to begin with?
At roughly 40:45 on the time-line when the scientists discover that shining a flashlight on the underground people makes them run away, you can see that half the king's mustache has fallen off.
When the mole men kidnap the scientists and pull them down the dirt holes you can plainly see that their hands are rubber gloves! Their long nails shake and bend like cheap rubber.