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.
Revealing mistake: When Robert and Julie are attacked by snakes outside the cave, notice that in the shots when you see the backs of Robert and Julie there are hardly any snakes on the ground (I counted one) compared to other shots. The shots of Robert's leg as he sweeps the snakes away are almost certainly of a snake handler instead of the actor.