Other mistake: When Robocop is being repaired by the homeless guys, you can see clearly his stomach going up and down as he breathes. If he's mechanical he shouldn't be breathing, and even if they kept that bit of his innards, he's covered in a titanium shell so we shouldn't be able to see anything moving anyway.
Other mistake: Near the end, just before the OCP building explodes, when Robocop flies carrying both girls to get out of the office you can see the wires that make this possible.
Other mistake: When Lazarus and the head of security concepts are talking about removing RoboCop's emotions, the other doctor speaks up and says that they could install a "microneuro barrier" that would block his emotions. He pulls the bag containing the chip from his lab coat without even looking at the pocket, conveniently. Seems a little unbelievable that someone would carry around a single purpose chip and know exactly where it was if RoboCop hadn't previously been giving them any problems.
Other mistake: The first fight of Robocop against Otomo ends when he blows his head off. Nothing dangerous happens. At the end of the film two Otomos lose their heads, and they self destruct.
Other mistake: After officer Lewis dies, the camera close-up shows her breathing. There is also eye movement.
Other mistake: The explosion at the gates to the Police Ordnance depot is utterly ridiculous. They blow up steel gates with dynamite, but the resulting explosion is a fuel type flame. It's metal they are blowing up, not a combustible material.
Answer: They wanted to make the film approachable to a broader age group. Kids were into Robocop, even though the movies weren't necessarily "kid friendly", so they made the third movie one that parents wouldn't mind their kids seeing in an effort to get more sales.
Phixius ★