In the movie The Mummy's Hand (1940), Wallace Ford's character is Babe Jenson. In this movie, Ford returns as a member of the original expedition thirty years later, but his name is now Babe Hanson.
Partway through the movie (at around 34 mins), John Banning refers to dust marks on the throats of Aunt Jane and of Jim (the dog-keeper). But Jim was not strangled by the Mummy; he fainted, and the Mummy contemptuously walked by him, accidentally kicking earth against his face. So there was no contact between the Mummy's wrappings and Jim's throat. Just possibly there could be some dust on Jim's forehead, as it looks as if the Mummy's foot glances off it as the Mummy walks by. But certainly there would none on his throat.
George Zucco confirms that while it didn't kill him (being set afire at the end of The Mummy's Hand), it "maimed and distorted" the mummy, which neatly explains why Lon Chaney Jr. looks nothing like Tom Tyler, it does not explain why the wrappings on Chaney's mummy are not even singed.
When the Mummy is first awakened and travels to the Banning house, one of the neighbors is awakened by a shadow moving across her face. She wakes up her husband to tell him. He then looks out the wrong window to try spot the cause of the shadow. The moonlight comes in from a different set of windows.
The aged Andoheb's voice wavers between a high-pitched, quavery, "old man" voice and a deep, resonant one from shot to shot. He is also bald in flashbacks but sports full head of white hair 30 years later.
When a torch is thrust into the mummy's face, it is clearly a rubber mask on a dummy.
When Kharis strangles Jane Banning, you see his disfigured, immobile eye illogically flutter; it's Lon Chaney's eyelid moving behind the thin rubber of the mummy mask.
A tombstone can be seen shaking around 18 minutes in.
Whenever the Mummy's feet appear, it is clear that they are shoes or slippers with bandages applied to them, separate from those on his legs. This is particularly evident when it climbs the trellis outside the Banning home toward the end of the film.
Kharis never uses his right arm until he carries Isabelle with no problem.
During George Zucco's brief transfer of power, the voice is clearly (and badly) dubbed and the lips frequently do not match the words being spoken.
Near the beginning of the film, Stephen Banning recounts his encounter with the mummy to his family. While Banning is narrating, clips from the previous film, The Mummy's Hand (1940), are shown in the form of flashbacks. Banning is able to recount the final conversation between Professor Andoheb and Dr. Petrie despite the facts that nobody else was in the room with them, Dr. Petrie was killed by the mummy before he could leave the room, and Professor Andoheb was wounded and presumed dead. Even if he was able to piece together what happened to Dr. Petrie based on the evidence, Banning would not have had the perspective to recount the conversation.
When Professor Norman examines the mummy's wrap he states that the chemicals used in the linen were used for embalming, but the mummy wasn't embalmed; he was in fact buried alive.
Stephen Banning is clearly an American, yet his sister, Jane, has a distinct Scottish accent - the result of casting the very Scottish Mary Gordon in the role.