Well said, all around. Wacky romps aren’t my favourite genre of Who, but they’re fine, and this is fine.

And I think there are advantages to starting a companion with a wacky romp - when there’s a lot of exposition to burn through, it’s probably not a great idea to have an overly complicated plot on top of it all. And the exposition is pretty well done - Gatwa’s “gone” when Ruby asks him about his people is a uniquely sublime line reading.

If the episode is missing anything that would make it work better, I think it’s a scene that “humanizes” the bogeyman before it ends up in the airlock. Thinking back to “The Beast Below,” another wacky second outing for a companion, there was at least a trail of clues for Amy to consider that helped her conclude that the space whale was benevolent. “Space Babies” lacks that, and while “compassion for compassion’s sake” is probably the better message, it’s also a much harder message to sell in the moment.

In retrospect, it’s interesting to see the Doctor sieze upon the apparent coincidence of having another adventure involving babies, which gets the Ruby’s birth is important narrative going. Knowing that the point of it all is that they gave it importance over time, it’s neat to see that beginning here.