In the beginning, it looks like the office's front door leads out directly to the street outside. However, at the end when he and his wife leave the office, the view is down a long corridor, as if his office is inside a building.
When Arthur Curtis first sees his wife in his office at the very end of the shot, the film goes in reverse for less than a second. You can see Arthur Curtis move backward and Mrs. Curtis' handbag swing back abruptly - both in the exact same motion as when going forward.
When Arthur/Gerry is trying to make the first phone call, right before he dials the third number, the shadow of the fake wall can be seen sliding.
When Nora drives up to the house with Arthur, she has the hi-beam headlights turned on her car even though it is daylight out.
After they both walk in the house she never turns the headlights off.
Gerry Raigan leaves the studio lot with his wife. He races back-and-forth through Los Angeles traffic dodging cars. This appears to be stock traffic footage because it doesn't match the rest of the digital copy and all the cars appear to be from the late '40s or early '50s.
As the little girl on Ventner Road points out Arthur Curtis, she can be heard saying "That's the one, Mommy, that's the one, Mommy, he's the one that grabbed me. He scared me." But her lips aren't moving.