Movie is supposed to take place in 1978 but the scene during the credits shows a flyover of a pier with an amusement park on it with roller coasters that were not of that design in the 1970's.
At 19.57 mark, the queen of hearts card that Doc shows to make the winning hand is clearly a larger font card than the rest of the cards. At 20.03 the hand is shown again and all the cards are the same font size again.
While talking to Carson at the bar, Rose's dress strap switches between dropped off her shoulder and on her shoulder several times.
When Travolta gives the hotel clerk $100, it is clearly a $100 bill. However, when the camera cuts instantly to the clerk with the bill in his hand, it is clearly a one dollar bill! Also, the $100 bill is the design that was introduced in 1996, and this movie is set in the 1970s.
During the shootout at the Hospital Travolta fires 8 times between reloading his 6 shot revolver.
An earlier comment stated there were no shots of the Seawall. Actually there is a shot of it showing the Flagship hotel which would be correct in 1978. However there is also a shot of an amusement pier which REPLACED the hotel after Hurricane Ike in 2008. Also, the Seawall has NEVER been 50' tall. It has always been 17' since the original 3 mile section was built between 1902-1904. The subsequent 8 miles of Seawall were also 17' tall making it the longest continuous sidewalk in the world.
In 1978 there were no casinos in Texas. Even today there is only one, slots only, 15 miles East of Livingston, TX.
The football team represented as being in Galveston was Texas State University which is located in San Marcos, Texas, which is 216 miles from there.
Patient Geraldine shoots Dr. Chambers in the back with a shotgun that was shown earlier to be loaded with buckshot. Buckshot makes several holes in the target, but the entry wound in his back is a single hole.
When Carson's daughter is visiting him at the motel, he holds up a donut to show her. The scene switches to her face for a moment, and then back to him. A large piece is now missing from the donut but he is not eating it. A moment later he takes a bite.
The movie is set in 1978, which is evidenced in the 70s-era vehicles, and the common usage of revolvers by Chief Walsh (Robert Patrick) and Carson Philips (John Travolta). Yet, during the shootout, at the sanitarium, between Carson and Lorenzo (Blerim Destani), Lorenzo is clearly shooting a Glock pistol (visible beginning at around 1 hour 18 min, when Lorenzo is shooting from behind the pickup truck), a weapon for which design work would not begin until 1979, let alone enter service in 1982 with the Austrian military and police. In fact, as the scene progresses, it appears it might even be a 2nd or 3rd generation Glock pistol.
Carson talks to the Coroner about possible drugs in the dead football player and the Coroner said he sent the sample to Dallas. This makes no sense because it would have been sent to Houston which is a short drive away to the east vs Dallas which is several hundred miles away.