Continuity mistake: Just before Scorpio crashes, Avon grabs Orac and teleports to safety. When they're still aboard the ship, Orac has several wires hanging loose from underneath. When they materialize on the planet, however, all the loose wires are magically repaired and no longer hanging. (00:16:30 - 00:17:45)
Revealing mistake: Scorpio is attacked upon entering Gauda Prime's atmosphere. The ship lurches left: everyone leans left and hangs on. The ship lurches right: everyone leans right and hangs on. The ship rolls over a full 360 degrees: no one leans or hangs on, nor do they fall out of their unbelted flight chairs. And oddly, those same chairs that held fast here tip over with ease later, when Avon escapes with Orac. (00:13:45 - 00:16:15)
Revealing mistake: When Scorpio flies from its launch bay cut in the Xenon cliff face, it's broad daylight (and no, the planet does not have twin suns) - but the ship casts a shadow on the cliff above itself. There's no possible light source from that angle other than studio lights on the ship model. (00:01:20)
Revealing mistake: Avon & Co. are supposedly racing through the woods and cloudy skies of Gauda Prime in a flyer. But the reflections on the vehicle's windscreen never move. (00:38:45)