Near the end of the movie Mr. Moto begins a fight with Bokor's bodyguard. The bodyguard lunges at Mr. Moto and takes the first swing with the sword. The bodyguard's sword breaks in half, but in the next shot they they continue this sword fight, but with no broken swords.
The camera being used by the newsreel cameramen has an electric motor, not the best choice for use in the remote jungle.
Mr. Moto explores the underground munitions dump without any visible source of light.
When Moto, in the guise of the elderly guru, is charming the snake in the basket, the wire operating the supposedly live snake is visible.
The first time Moto reaches for a carrier pigeon to relay a message to his government contact, you'll see that the cage door is already open.
If the cover over the underground chamber were actually made of solid stone, it could not be opened so easily.
In the underground chamber, when the cans of gunpowder are knocked over, the sound reveals that the cans are empty.
When Mr. Moto climbs out of the archaeological dig, his white suit is completely spotless.
Chick drops an equipment case just before falling into the tiger pit; when he climbs out, he does not retrieve the case and no one misses it.