When young Jake first goes to the mall with his family he, at time stamp 48:22, passes a lady in a red coat with a white blouse and black skirt. Then later in the movie on a different day during the second trip to the mall at time stamp 1hr 13:21 the same lady is seen again wearing the same clothes as she walks past the moms who are holding signs. This suggests both parts were filmed at the same time.
The NES Power Glove needed a set of three ultrasonic receivers set up around the television, which are conspicuously missing when it is used.
When Jake's family goes to the mall they have two life like animatronic Dinosaurs. One of which was moving. Since this film was set in the late 80's they still didn't have this kind of technology until Stan Winston's team built it for the Jurassic park(1993) movie in 1993. A life like Jurassic park animatronic dinosaur was built in the 2000's for the Times Square Toys R Us in NY.
When Jake is playing Nintendo in the mall the red light is on but the power button is not depressed, meaning the Nintendo should be off.
Jake visits the mall on two different days, but some of the same shoppers are there wearing the same clothes on both days.
When Jeff brings the green paper with the win a Nintendo sweepstakes, Josh grabs it from him, and it is very crumbled but when Jeff takes it back it is straight again.
The date on the video camera says 12/25/1988 which is one year before the Power Glove hit the market.
The Billy Ripken profanity card is from Fleer's 1989 set, and the film takes place in December 1988. Even if the cards had been released early, the indication that it was an "error card" and worth $95.00 wouldn't have appeared in collector magazines so soon.
Although Cabbage Patch Kids were in high demand in the early 1980's, by 1988, the company had filed for bankruptcy and licensed out the product to multiple distributors, thus were easier to find. It's highly unlikely they would've "sold out in 20 minutes" from a Chicago toy store in the late 1980's.
A student can be seen wearing a Pantera Projects in the Jungle shirt. Pantera didn't break nationally until 1990 with the release of the Cowboys From Hell album, and by that time, they were using a different logo than the one seen on the shirt.
The movie takes place in 1988. The orange NES Zapper was not released until 1989.
In the parent meeting about banning video games the police officer is wearing a coat with the Chicago flag on the sleeve. Batavia, IL is not a part of Chicago. They are not even in the same county.