The playback of the nurse murder and countdown is altered from what we've previously seen. In addition, the countdown starts from eight - albeit he may have fast-forwarded the tape to the crucial part; when he first plays the tape back, there's white noise before the countdown from eight.
The sounds of the drive-in movie advertisement can be heard repeating some bits, several times.
A mustached sanitarium patient is given a yellow party hat and noise maker, yet in a medium shot, his noise maker disappears.
The countdown in New York only takes 57 seconds in the movie, especially the 20 and 15 second remarks as they're counted down a few seconds too soon.
At one point a psychiatrist says that the killer is "mutilating" the breasts of his victims, however, when the bodies of the murder victims are found there are no injuries to their chests at all.
At one point the killer hits a cop over the head and takes his uniform. Despite the cop being quite a bit heavier, the uniform fits perfectly.
When Derek takes the three pink pills then drinks water at least one pill is visible moving around on his tongue behind his teeth.
Co-producer Yoram Globus's name in opening credits is mis-spelled "Yorum".
Toward the end, when the cops are casing the hotel, there is a crew member kneeling behind kitchen equipment that one of the cop walks behind.
After the killer pulls over and threatens a couple drunks, the shadow of either a cameraman or crew member is visible on the drunks.
Camera shadows visible in some scenes.