At one point during the chase where the sheriff is following Paul there is a close-up of the top of the police car where the flashing light is not lit. Then it cuts to a full view of the car where it is flashing. In other scenes the lights are flashing at all times.
The Sheriff says he's in Palms, California, pop. 2,500. There was an actual town in California called The Palms that incorporated into the City of Los Angeles in 1915, became know simply as Palms, and became one of the most densely populated districts of what, in 1963, was the 3rd largest city in the U.S..
When Paul sits up and looks at the dead Mrs. Hotchkiss in the back of the ambulance and screams, Mrs. Hotchkiss begins to close her eyes after being dead for quite some time now. Her eyes blink too.
After Mrs. Hotchkiss is killed by the hand she is clearly seen breathing.
On Steve's desk is a "Rocket model". This same rocket model is seen on Chief Meidel's desk.
During some of the scenes inside Mrs. Hotchkiss home, you can hear dogs barking in the background.
When the hand attacks our hero while he is driving the car you can clearly see the head of someone reaching over from the back seat.
When Marta puts on her bikini bottom after supposedly disrobing behind the rock, she pulls them up over her panties. This goof is only noticeable in the full-screen (open matte) version of the film. When cropped for wide screen the illusion of nudity is preserved.
When Steve Curan is talking to Barrenger in his office, he says "a murderer has been committed" rather than "a murder has been committed."
Before Paul attacks Marta, she immediately clutches her neck before he even touches her anywhere on her body, at which time no incriminating evidence had been found linking him to his aunt's death, only the dead astronaut's fingerprint (off his Crawling Hand) was found at the scene, so she had no reason to anticipate strangulation in particular from Paul..