Factual error: When Shep and his partner are looking for Frank on the docks in 1969, the camera pans to the left and we see a flash of the (completed) World Trade Center buildings just before the cameraman catches his error. In 1969 construction had only just begun on the towers.
Factual error: The radio used in the film is a Heathkit SB-301 receiver only, and is, in reality, incapable of transmitting.
Factual error: In the year 1969 Dennis Quaid reaches into a pile of Albums (vinyl) to play the "King". One of the albums in that pile is "Elvis In Concert" which was not released until 1977.
Continuity mistake: When John is telling Frank Sr. about game 2 and about Al Weiss, the scene changes to the fireman sitting near a TV watching the game. As the camera pans around a fireman with a moustache is sitting behind the old guy in the chair, but in the following shot he is sitting at his side.
Continuity mistake: After the first time the mother disappears from the family photo, and the father and son are talking after the father "saves" the first nurse, there is a wide shot of the board with the family picture on it - and it shows the mother in the picture. When the camera zooms in on the picture, the mother is gone again.
Continuity mistake: In the scene near the beginning where John is looking through a scrap book, he turns the page and there are articles on the page, but when the camera does a close-up on the scrapbook, there is a whole newspaper with the scrapbook.
Continuity mistake: When Satch is talking with Frank after discovering his wallet underneath a dead girl, he lifts up Frank's driving licence. Four of Satch's fingers are on the front side of the licence, but when the shot changes, Satch holds the licence with three fingers on the front and a finger and thumb at the back.
Continuity mistake: At the very end when the family and friends are playing baseball in the park, the first ball Frank hits smashes into the headlight on Gordo's Benz. The front-end license plate is shown for a few seconds, and even though it is blurry, it appears to be several numbers and maybe a letter or two. But when the next shot of it is clear, it says "1YAHOO".
Continuity mistake: When Frank has survived the Buxton fire and is trying to reach his son in the future over the radio, his son from that time walks in and sits on Frank's knee. He takes a chewing gum out of the silver wrapper in his right hand, but in the following shot it is now in his left.
Continuity mistake: In the scene where Dennis Quaid by accident sets the desk on fire, we see how the burn mark appears on the desk in 1999. But why is it still hot and smoking 30 years after? Same goes for the writing with the soldering iron. In comparison, the wallet has got signs of being 30 years old when the son finds it.