Factual error: The nickel from the phone booth is fake. Unless it was a special minted edition. It doesn't look like any nickel I've ever seen from that era. It is also reflectively discolored compared to the proper coin to its left. It actually looks more like an '01 coin.

Continuity: When Chris is hit by a car, he has both shoes one when he is rolling on the ground. One of them disappears in the following shot.

Factual error: When Chris, and his son go to (at the time) Candlestick Park, home of the San Fransico 49ers, you can plainly see both when he is outside of the stadium talking to guys in the parking lot and when he's in the 'suite box' trying to get the guy to do business with him that all of the logos for the 49ers are from this time period. This is a huge mistake considering this movie was set in the early 80's whereas the 49ers did not begin to use black in their uniforms again until the earliest being in 1994 for the NFL's 75th Anniversary, which was the last year they won a Super Bowl, defeating the San Diego Chargers. The team didn't go to 'black' as a primary color in their scheme until 1996 when they added the black outline around their logo (which you see on the walls outside the stadium and on the field as you see the team playing) and by also adding it to their trademark sleeve stripes and around the their numbers which were given a drop shadow style as homage to the '94 year uniforms. They did however wear the correct 'era' uniforms which would be considered a 'throwback' uniform by today's standards.

Factual error: The abdomen x-ray in the first doctor's office that Will Smith visits is upside down, evident by the pelvis seen at the top.

Continuity: When Chris is at the job interview and is full of paint, a lot of paint is on his neck when he's going to the interview and at the beginning of it. But after the interview and at the end the paint disappears.

Continuity: Will Smith's son is given a basketball as a gift. Later on, when he tells his son they are gonna go back home, he says, "We are gonna get you home to your football."

Continuity: In the scene where the cabbie is chasing Will Smith, the cabbie can't be seen entering the subway station using the stairs or the escalator, but pretty much appears to come out of nowhere.