Gaffes

Dr. Blatnoyd's office cannot possibly be in a large corner room with large windows on both sides based on the exterior shot of the Golden Fang building.

In the same café scene with Doc and Bigfoot, Doc takes a drag off of a cigarette and clearly stubs it out in the ashtray with his right hand. Bigfoot then tells him to pick a card, which he does. Doc looks at the "card", taking a deep drag off another cigarette with his left hand. There was no time in between cuts for Doc to have lit another cigarette.

When Doc is talking to the girl in Dr. Blatnoyd's office, the name plaque on Dr. Blatnoyd's desk disappears and reappears.

Dr. Rudy seems to have dropped "that bottle" when he pulls down his pants running to check out the problem with his couch in the office.

When Doc and Crocker Fenway are meeting at the restaurant, Doc retrieves the same folded linen napkin from the table twice, once from each camera angle.

When Doc goes to see Penny at her office she asks if he will let her depone him. While the use of the word "depone" might seem unusual compared to the more common "depose", this should not be regarded as a mistake. Penny's actual line from the source novel is this: "Would you be willing to depone for me?"

In the car (uni color Mercedes) with Doc, Dr. Rudy Blatnoyd, Japonica Fenway and Denis, as they are being stopped by cops for being under suspicion of a possible cult: japonica was the driver the entire time. When the cop comes back to give them their id's back. Doc is in the drivers seat. However, this can be explained: When the cop approaches the car Japonica asks if he's "The Great Beast" and when he says she was driving without headlights she says "But I can see in the dark", to which the cop replies "Perhaps you shouldn't be driving then". Since the cop has clearly indicated he doesn't think Japonica is in a fit state to drive, It only makes sense that she wouldn't be behind the wheel when the he returns from checking their IDs if they hope to be able to drive out of there.

In the restaurant discussing the Golden Fang, Doc and Sauncho Smilax bring up Howard Hughes and his purchases in Las Vegas real estate. The movie takes place in 1970, Howard Hughes dies in 1976, yet Doc refers to Howard Hughes in the past tense when he says, "Howard Hughes was Italian?" as if he were dead.

The customer service number on the back of the American Express Card that Doc receives from the Gold Fang family has a toll-free area code of 888. 888 didn't become available as a toll-free area code until 1996. A toll-free phone number for a 1970s customer service line should have been 1-800-XXX-XXXX.

Though the film is set in 1970, one scene of a phone conversation between Doc and Bigfoot shows Bigfoot using a Sculptura "donut" phone which was not available from AT&T until 1977.

There are five doors that slam when the crew is leaving Dr. Rudy's office to drive to the beach into Japonica's Mercedes; Denis slams his door twice.

At the dentist's office the receptionists asks for "contact information"- a term not coined until the 21st century. In 1970, one would ask only for "a phone number" or "address."