Deliberate mistake: When the board member is shot up in the beginning by ED-209, in one or two shots you can see the bullet impacts happen about 1/2 a second after the shot starts (Criterion DVD version).
Visible crew/equipment: When ED-209 is being demonstrated for the first time and goes out of control, when the young executive is being shot, repeatedly, by ED-209, you can see packets of red paint strapped to his back, under his suit.
Continuity mistake: When Murphy and Lewis are chasing the villains in the beginning, one of the bad guys shoots the windshield of the cop car, leaving a hole and messing up the glass. Not even a second later, the windshield is fine.
Continuity mistake: When Robocop is fighting Clarence Boddicker in the cocaine factory he throws Boddicker through a plate glass window. If you watch closely, you can see the window shatter about 1-2 seconds before he goes through it.
Factual error: After Robocop stops the criminal from robbing the convenience store by bending his machine gun, the robber tries to run past him, only to get clotheslined by Robocop. The direction the robber flies after getting hit defies all physics.
Continuity mistake: When Robocop looks up his old address, his house number is the 500's on Primrose Street, but when he drives by the sign on his street it says he is in the 3000's section.
Visible crew/equipment: When Clarence is racing away from Lewis near the end of the movie, the camera zooms in on Clarence driving the car and the camera men and camera truck are visible in the reflection of the car.
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.
Continuity mistake: Just before Clarence Boddicker crashes his 6000 SUX into the water after colliding with Lewis' Taurus Cruiser, there is a scene where his car is charging toward the camera, and a hubcap comes off and whistles past the camera, in fact they even put in a sound effect. But in one of the next shots, the hubcaps are back on.
Visible crew/equipment: In the scene where all the OCP executives are listening to Dick Jones presenting ED-209, and while the "old man" starts talking about Delta City, watch when the camera moves along backwards to show the city model he's talking about and you can see reflected on several TV sets that are on the wall both the camera operator and another man behind him, perhaps the boom operator.
Continuity mistake: When Clarence is talking with the other drug dealer in the warehouse, tempers flare and guns are drawn. The Asian gang member racks his shotgun (thus loading the weapon). Wouldn't he have kept it loaded? Anyway a few seconds later Robocop enters and the same Asian guy racks his shotgun again and no shell is ejected.
Continuity mistake: Dick Jones brags (admits?) to Robocop, "I had to kill Bob Morton because he made a mistake. Now, it's time to erase that mistake" while Robocop is crouched on the ground, looking away from him from across the room. In the playback, Jones is facing the camera as though it were videotaped or filmed in a studio.
Continuity mistake: When Clarence's car is flipped over at the steel mill, he gets out and starts firing at Lewis. Look at the windshield on Lewis's car. It's in perfect condition and all of a sudden 9 bullet holes appear in it. Clarence didn't even shoot his gun that many times.