Visible crew/equipment: When Dr. Faxx is programming the new directives into RoboCop, the camera pans around RoboCop's body. You can see the reflections of a camera and a crew member on RoboCop's helmet. (00:47:55)
Visible crew/equipment: When Robocop visits Cain's hideout and sends his car in as a decoy, after he returns to the car, watch the driving shot closely. A wire has magically strung itself across the entrance and attached itself to the back of the car - it wasn't visible from an earlier shot. As the car drives forward it stretches the horizontal wire, and just as a tiny amount of pressure is exerted, the car explodes. Yeah, it's technically a mistake, but I think it's more worth checking out just to see how those tricky effects are achieved.
Revealing mistake: Just before RoboCop gets out of the car to walk towards the baseball coach, Lewis shoots at the coach and he jumps back. Watch carefully. Whilst jumping, his hat comes off slightly and you can see the make-up for the hole in his head, which he doesn't receive for a few seconds after this. Seen best in Slow motion on the DVD. (00:50:31)
Continuity mistake: After turning off the hydrant, Robocop is talking to the kids. As he does, a girl puts graffiti on his back, and sprays paint on his head. After they run off, you see very little color from the paint, then a moment later, the orange paint is totally visible.
Continuity mistake: When RoboCain kills the chubby man with a moustache, his jacket falls down in the back shots, but it's perfectly fit in the front angle. When he finally collapses, it's falling down again. (01:19:50)
Continuity mistake: A man fires a rocket at a police car driven by Robocop, but when the car overturns and it's shot at, one can see it's empty. A moment later, Robocop opens the door and appears out of nowhere.
Continuity mistake: Robocop shows up at the presentation of RoboCain, but he disappears in the wide shots, only to suddenly reappear when the shooting starts.
Continuity mistake: When RoboCain steals the remote control, there's a woman in black walking up the bleachers. A shot later, right when RoboCain clicks the button, the woman is suddenly way behind.
Continuity mistake: When Robocop lectures the kids about the hydrant, they are suddenly standing closer together between the first and second shot.
Continuity mistake: When RoboCain smashes Robocop against the wall, the shape and size of the hole, plus the cracks around, change 4 times during the fight, depending on the shot.
Visible crew/equipment: When Robocop talks to the baseball kids, the moving boom mic is reflected on his helmet.
Revealing mistake: When the truck drives through the bar, the brick walls are a blatant thin piece of painted cardboard.
Revealing mistake: After Robocop kills the man holding a baby, one can see the baby is a doll.
Answer: We're never given specifics about it, but we do know it's the most addictive drug in history.