Revealing mistake: When running towards the "bear attack", Sean activates the Guyver. Close ups of the armor attaching itself to his body show that's not really Sean as his arm and leg are both seen not moving even though he's running to where the attack is occurring.
Visible crew/equipment: Throughout the movie, in the shots of the guys on the alien planet, the white reflector screens and film crew's reflections are visible in their sunglasses. (00:40:20)
Other mistake: As the Veridian star is destroyed, Picard raises his hand to supposedly shield his eyes from the sun's light, but he is looking in the wrong direction; the sun is behind him, and there is no light on the rest of the front of his body.
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.
Continuity mistake: When Schwarzenegger's urine is tested for pregnancy, the colour of the contents of the vial does not stay the same for two consecutive shots.
Plot hole: The whole plot of this movie stems from a scientist selling his time machine to a corporation for further funding for development. He has a TIME MACHINE. Lotteries, stock market, 100 years of interest on a savings account. Why does he need more funding?
Deliberate mistake: When the recon team head out of the base they encounter a robot. But it is a probe droid, distinguishable by the lack of a cannon on its right arm. The only probe droid that the lab sent out self-destructed back in the 1970s, the rest were all sterilisation units. (00:39:05)
Continuity mistake: When Connor is escaping from the psychiatric ward you can clearly see the cameras running tracks on the floor.
Audio problem: When the man with the peg leg is trying to resist getting a shot of anti-smallpox serum from Professor Waldman, he yells, "You're not sticking that in me. You're not sticking that in me." But if you look closely, you can see that his lips are not moving. (00:32:45)
Continuity mistake: In the scene where Dhalsim changes the programming, all the computer shots of Blanka show him with normal skin, despite that it's turned green.
Visible crew/equipment: When the spheres fly through the air you can see a "dot" following which is the camera.
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.
Audio problem: When the good guys finally get the Chevy V8 running, the sound it makes sounds more like a moped than a high-performance engine. It has headers and no mufflers, so it should have been quite loud.
Continuity mistake: Once they have the car wreck in the ally, a bird's eye view shows the good guy's car still having the exhaust at the top with fire coming out as they open their doors to get out. Very next shot, still showing them getting out, the fire is now out.
Revealing mistake: When the doctor is cutting the forehead, a red tube to release fake blood can be seen behind the scalpel. (00:30:12)
Revealing mistake: Most of the police cars are late model Ford Sierras, but any police car that crashes has been substituted for a much older early model Sierra.