I'm enjoying Jo's initial hesitation about exploring space it shows of her curious side and her enjoyment of the relative safety of earth in comparison to the doctor's urge to explore. The lizard creatures are LITERAL LIZARDS (I think they are iguanas but not 100% certain) filmed up close to make them seem massive -I love this show so much!!! however the primitive creatures motivations are very unclear and the overarching plot seems to be earth at war again.