When Craig is sinking in quicksand he shoots eight shots from his six-shot revolver.
Differences between interior and exterior of the house: the front door, the staircase, the window "under" the lake.
In both scenes, when Tillie is talking to Lawton and then with Capt. Robbins, the pencil she has tucked behind her ear can be see when she's filmed from behind, but when she's filmed head-on it disappears.
After Lobo frightens off the two hunters in the torrential downpour, he returns to inside the mansion completely dry.
When Dick Craig goes to push the boulder toward Dr. Vornoff, the policeman who tripped and sprained his ankle is suddenly absent.
The hydrogen bomb exploded at the end would have left scorched earth, radioactivity, and total destruction of everything for miles around, including the survivors of the monster, shown in the following shot.
Explaining his experiment, Dr Vornoff says it uses the process of fission. while the hydrogen bomb shown to be the ultimate result operates by means of fusion. Fission is the basis for the A bomb.
Many movie sources cite that in this film Bela Lugosi flubbed a line in which he described Lobo as being "harmless as a kitchen". Legend has it Edward D. Wood Jr. didn't have time or money enough to do a second take. But on watching the movie, one discovers that Lugosi says the line correctly.
When Dr. Vornoff is speaking to the woman before using hypnosis for the first time, it was thought for a long time that the shadow of a boom mic is visible on the wall behind them, but it is a mistake. At 35min, the second times he uses hypnosis on the woman, you can see that it's actually shadow made by the shackles on the wall.
Obvious rubber dummy for the octopus in several scenes.
When Lobo is thrown at the door by the stairs leading to the
lab, the entire side of the set moves.
Someone answers the phone even though it didn't ring.
Obvious stunt double for Dr. Vornoff during the final confrontation scenes. The double was shorter than Bela Lugosi so to compensate, the double wore platform shoes that can be seen during the struggle.
Obvious insert shots of Bela Lugosi following his kidnapping Jan and leaving the house. One is of him looking back at his house on fire, the others are when the police are shooting at him. He is not even on location, he's in a black sound stage. The shots fired are dubbed, but his "reaction" is completely off. He's just standing there frowning.
Dan Hill's final line "He tampered in God's domain," is obviously a cliched rushed line thrown in to end the movie.
In the opening titles, the Copyright date is shown as MCMXCV [1995]. It should be MCMLV [1955].
Several characters travel back in forth, in journeys that last a few hours at most, between a small town in California, and Dr. Vornoff's swamp, which appears to be either a Louisiana bayou or a Florida Everglade.
At one point, Lt. Dick Craig calls Martin "Mike" instead of "Mac."
In Vornoff's Lab, when Lobo is about to clobber Craig, Lawton is on the table and screams "Steven!"