Other mistake: In the scene in the shooting range where Robocop's firing skills are being tested, as the shot focuses in on Officer Lewis, the last cop in the row next to the wall, two spaces to her right can be seen holding his empty gun at the target but not moving it, reloading it, or firing it. It seems as if he is frozen. (00:32:25)
Other 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. (01:29:00)
Other mistake: Just after Dick is fired, Robocop shoots him. Robocop shoots Dick twice and we see two exit wounds on Dick's back. Robocop fires a third time, and two more exit wounds appear simultaneously lower down. (01:35:50)
Answer: When Bob Morton is told by a tech that one of Murphy's arm was saved, Bob stated that he wants total body prosthesis. Meaning Robocop's entire body was synthetic. None of his actual body was used. The only thing that was used was Murphy's actual face.
Also, his human brain, and possibly his spine, where OCP could wire him into the suit.
Movie Nut