Continuity mistake: When Diana is being chased by Donovan after crashing her craft, she has her normal human eyes. But during Donovan's strangulation attempt she has lizard eyes. As we saw in the original series, a Visitor's human eyes had to be removed by hand before the lizard eyes could be seen underneath.
Continuity mistake: After a talk with Diana on the mothership, Lydia is left alone and then she takes a message out of her uniform. She wears a ring on her left middle finger and her nails are painted red. In the following shot we see Lydia's hands put the message into a box. The hands do not have their nails painted and wear no ring whatsoever.
Continuity mistake: Mike Donovan (riding a horse) is chased by a Visitor shuttle. It is obvious that there were recycled some shots from "The Final Battle" (Ep. 1). In "The Champion", Donovan does not have a laser pistol. However, there are some shots in which he has that pistol: obviously, those shots are taken from TFB.
Continuity mistake: When Charles reads the message about Nathan Bates coming out of the coma, there are two things to look for during the closeup of the note. The logo on the top is replaced by writing and he grips the note in a different position from before. The writing changes yet again when the note is seen from behind.