Plot hole: In the opening scene we see Mike and Kyle driving in the truck. Kyle remarks that Mike has been driving since midnight and it is broad daylight outside. So they have supposedly been driving for several hours. Yet they start talking about their mission as if they have only just got in to the truck. As anyone who has been in that kind of situation knows, everyone always discusses the important stuff at the start of the journey, so it is clear that the scene has been poorly scripted.
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.