After Cantrell leads McCloud away from his business manager, they discuss Cantrell's pills. In the shots where they face each other, the taller McCloud looks down at Cantrell. But close-ups on McCloud show him looking up, as if facing a taller man.
After McCloud leaves the room to get Mr. Cantrell's mints, Cantrell looks over at Stevens. Stevens' reaction shot is printed backwards.
Elisha Cook Jr.'s character is called Mr. Rafer by McCloud, but identified as Mr. Diller during the end credits.
After Clifford has left the Cantrell estate, while McCloud and Broadhurst wait with Cantrell and Stevens, the phone rings. At this point the boom appears at about 11 o'clock on the TV screen.
When McCloud confronts Cantrell in his home with his files, the boom appears at about 11 o'clock on the TV screen.
When McCloud produces the file he took from Cantrell's office, Clifford tells him he didn't have a search warrant. McCloud answers by saying that it was okay since the secretary had given him the folder. That would have not made any difference as only with Cantrell's explicit approval (outside of a warrant) would it have been admissible in court.