Deliberate mistake: After the trilithium missile hits the sun, it is shown going out in real time from Veridian III. As the planet is relatively earth-like, it is several light-minutes away from the sun. The filmmakers wanted it to be obvious that the missile was successful, so they ignored the speed of light. (01:20:35)
Factual error: We're told they carbon dated the gold to determine its age. Problem is, the gold hasn't aged by the normal processs - as it's been brought forward in time it will appear to be extremely new. As such carbon dating wouldn't work. Also, carbon dating only works on things that were alive and absorbed carbon-14; gold, having never been alive, could not be dated this way.Jon Sandys
Character mistake: When Guile promises to rescue the hostages while on camera with Bison he makes a point to mention Charlie by name to reassure him that he wasn't forgotten. Anybody who was in charge of a major recovery operation would know better than to mention a specific hostage that isn't already well known to the enemy because he just put a target on that hostage for further abuse. This was promptly shown in the following scene when Bison picked out Charlie to be transformed into a beast as a result of Guile identifying him as a personal friend.AD
Revealing mistake: As Mary, Sam, Jarvis and Andrew are speeding away from the TV station, one of the boys from the UFO crashes his bike head first into the car. This causes the boy to crash through the window. When he does this the window shatters like a plate glass window instead of the safety glass that is a standard to be used for vehicle windshields.
Revealing mistake: When they are stopped after curfew by the Mohawks, Hawk jumps at the window and orders them to give them 50 bucks to go on, and they accept credit cards. When saying this, you can see the dividing line between his real skin and the fake head cap that supports the actor's fake hair.Quantom X