Revealing mistake: After the one bad guy crashes into the giant vat of Toxic Waste, hardly any of the liquid from the container spills out for the first two shots. Then a few cuts later, almost all of it pours from the back of the truck. Judging by the size of the hole it left, more liquid should have been coming out around the truck, not just through it.
Revealing mistake: In the firing range scene, before Officer Lewis puts her gun down, and leans forward to look at Robocop shooting, we see him fire three shots. Look closely the second time he pulls the trigger. He pulls the trigger, but there is no ammo sound, nor is there a firing spark. This is in the VHS version.
Revealing mistake: The film takes place in Detroit, but it is glaringly obvious that it was shot in Dallas. First of all, in the early scene where Murphy chases Boddicker's gang on the highway, Reunion Tower, one of Dallas's most famous landmarks, is visible in the background. Much of Dallas's skyline is also visible in the final scene where Robocop confronts Dick Jones in the OCP boardroom.
Revealing mistake: When RoboCop is getting into his car after remembering about his former life, and breaking out of the police station, look at the bottom of the screen. You can see that Peter Weller is only wearing half of the RoboCop costume, his right leg comes into shot as he gets into the car.