Revealing mistake: As Harry floats by the camera after the Black Hole grabs them, you can plainly see the wires holding him.
Revealing mistake: After the Palomino gets into the zero gravity bubble around the Cygnus, the camera goes inside to Pizer. He bucks in the seat a few seconds after the ship stops shaking, showing it was a camera trick.
Continuity mistake: There were two models used for V.I.N.CENT. and Old B.O.B., full-scale robots and miniatures. The miniatures are not identical to the full-sized robots. One notable difference in B.O.B. is that on the full-sized robot, his eyes are not flush against his face, so you can see the shadow of his eye sockets fall upon his eyes. On the miniature, the parts fit better so there is no shadow cast on his eyes.
