Factual error: During the part where they're in NORAD and watching all of the Soviet "nukes" hit various bases in the US, a base in northern Maine is listed as, "Loring AFB 43 Bomb Wing." This was a real air force base, but it was the 42nd Bomb Wing that flew B-52s out of Loring. The 43rd Bomb Wing did exist, too, but it was based at Andersen Air Force Base, Guam, in the North Pacific.
Factual error: The beginning starts out with two Strategic Air Command officers in a Minuteman Intercontinental Ballistic Missile (ICBM) Launch Control Facility (LCF) going through the strict procedures for launch of an ICBM. The crypto messages are being received by the LCF, the launch officers pull the launch sequence and confirm the crypto launch command (encoded message) matches that which is contained in the launch sequence - all very secret, and all very realistic. However, the missile they show in the movie powering up for launch is a Titan ICBM, and how you launch a Titan from a Minuteman LCF is beyond me.
Factual error: In the scene in which Prof. Falken shows David and Jennifer a dinosaur movie projected on a screen, Falken is between the projector and the screen, with portions of the image on his face, slightly blurry, just like it would be. But David and Jennifer aren't in the light path, so the only light on them would be reflected from the entire screen, but when they're shown, images from the dinosaur movie are perfectly focused on them, which would be impossible.
Factual error: While it makes for a great story for the movie, the reality is that all computer systems used by government agencies - especially in the DoD - are required to provide their source code for thorough inspection to ensure there are no back doors, hidden subroutines or other types of software code that are not relevant to the task designed for. Given the critical nature of this system being in control of launching nuclear missiles, the reality is that none of the games that Falken wrote - much less the whole routine to allow it to simulate a game like this - would still be in, for obvious reasons. Of course it could be argued Falken hid this, however given the lack of complexity for a computer of this era, it's highly unlikely.
Factual error: When Matthew Broderick sets up his computer to look for other computers by getting it to dial a number, check to see if it is a computer, record the number if it is, hang up, and repeat the sequence, the writers forgot one thing. With the type of modem he was using (a so-called "acoustic coupler"), someone would have to physically push the hangup button on the phone before it could dial another number. It could be entirely possible though to dial a number from the computer and send the acoustic coupler the instruction to generate DTMF tones, but this could only be done once; without an actual relay that will cut the line and get a new signal tone again, no looping (war dialing) could be done. The next generation of modems that hooked directly to the phone line could do all of the above, but with what the movie used, it was impossible.
Factual error: In two different scenes, Matthew Broderick lifts the phone receiver off his modem-once during the scene where it's dialing numbers in Sunnyvale, CA, and again when WOPR keeps calling his phone trying to reconnect. In both cases, the activity on the screen should have disappeared, since lifting the phone off the modem cradle disconnects the signal. Yet the computer somehow manages to keep dialing numbers, or display the running game clock on the simulation, without any interruption.
Add timeAndrew Bauer
Factual error: In the first scene with the computer (when Ally Sheedy visits) Matthew Broderick puts the handset on to the modem coupler with the cord toward him, then pushes the button on the modem which is facing him. A shortly while later he is at the computer and he puts the handset backwards with the cord away from him and pushes the button which is still facing towards him. The modem would not have worked properly, since it needs to send and receive through the respective ear and mouth pieces.