Continuity mistake: When the bearded man is robbing the convenience store, he demands that the owner opens the safe. Look at the Lite cans on the safe. When seen from the right, there are four cans. When the owner kneels down to try and open it, there are now three. When we cut back to a view from the right there are again four. Finally when the robber is shooting at Robocop there are only two. (00:33:20)
Continuity mistake: When Bob Morton, Johnson, and Kinney get off the elevator, a computer voice chimes that it's floor 95. After the board meeting, Morton and Johnson leave the board room (and it's the same floor as you can see the two paintings on the wall that lead to the board room) a sign next to the elevator says "120." (00:07:05 - 00:13:40)
Continuity mistake: When Clarence sets down the grenade on the table, we can see that there is a glass to the left of the grenade. When the view changes so we can see the whole room the glass has moved to the right of the grenade, then when we see Bob reaching for the grenade, there is no glass on the table. (00:58:34)
Revealing mistake: In the firing range scene, before Officer Lewis puts her gun down, and leans forward to look at Robocop shooting, we see him fire three shots. Look closely the second time he pulls the trigger. He pulls the trigger, but there is no ammo sound, nor is there a firing spark. This is in the VHS version. (00:32:10)
Continuity mistake: When the ED-209 gets to the stairs and tries to give the first step, its right arm changes from having one cannon and missile launcher to having two cannons and two ammo clips of sorts (just like its left arm). When ED slides and is falling, the arm changes back to normal; and at the end of the fall, its arm has two cannons again.
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. (01:29:50)
Continuity mistake: In the drugs factory, when Robocop starts to bang on the door, you can see at least 4 people on the stairs and overhead walkway. After Robocop knocks the door down and looks around, we see this through his view and they have vanished. They reappear when the camera view returns. (01:03:30)
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)
Revealing mistake: When they're supposedly tightening down the L.E.D. the scientist is using a normal drill bit attachment. (00:27:00)
Revealing mistake: As Emil is being washed out from the back of the truck by the toxic waste, it's obviously a stuntman. The stuntman appears to have a dark mohawk which does not match the actor's hair.
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). (00:11:55)