I can see this being told as a fairy tale to time lord children, it's basically just a retelling of Hansel and Gretel, and this time the Doctor Who twist on it still feels more fairy-tale.

Sure it's an alien planet, an alien threat, and there's technology mentioned, but the core of it is still much the same, and the Krillitane is seen as much more witchy through the lens of a child, which i think works to this story's benefit!