Revealing mistake: After Robocop goes through the windshield and grabs Cain, leaving the driver seat empty, in the long shot the stunt driver can be seen.
Revealing mistake: When the baseball coach is exchanging fire with Lewis, he reacts to a close impact. As he does, his arms brush his cap, and the makeup for the bullet wound on the upper left side of his forehead is revealed. When the fatal shot is fired, his cap is down in position again.
Revealing mistake: When Robocop punches through the door at the nuke lab it appears that one thickness of the door was removed ahead of time. When the guy looks through the sliding peep-hole it's obvious that the door is thick. But especially after Robocop removes his arm you can see it is only single thickness and you only see the shiny inner of the door peeled inwards and none of the brown paint from the outside.
Continuity mistake: At the nuke lab bust scene, Robocop knocks on a door that appears to open inwards. However, when the guy approaches the door inside, it's a door that swings outwards.
Continuity mistake: Cain's extraction in the glass tube had green eyes. Earlier he appeared to have brown eyes.
Continuity mistake: During Cain's escape attempt RoboCop seizes someone's motorcycle. The motorcycle's lights vary between being on or off throughout the scene.
Continuity mistake: While Lewis is shooting the baseball coach, she makes two holes on the glass of the van but they disappear when Robo is holding the dead body.
Continuity mistake: When the girl is spraying graffiti on Robocop, the last mark on his head is a light dot. Yet a moment later when shooting at the smoker, it's a bright orange line.
Visible crew/equipment: As Robocop is stood up after electrocuting himself, the crew and equipment is reflected on his front.
Revealing mistake: When Robocop is on the bike, he does a skid. in the exact place where he does this, there is already skid marks from previous takes.
Revealing mistake: The Mayor looks into the armoured van at the money, and picks up a gold bar. It looks bad, is obviously too light to be gold, and doesn't clink when put back.
Continuity mistake: When "Robocop 2" goes beserk, he shoots several civilians and a row of OCP security. The last civilian to be hit in that scene is later seen being helped down a flight of stairs by two folks as the President of OCP talks with some of his subordinates about who to lay blame on for the incident.
Answer: We're never given specifics about it, but we do know it's the most addictive drug in history.