I wonder if this story would have been more effective with some prior setup. As it stands, you’re abruptly introduced to the sins of this eternal race, and then the Doctor very suddenly brings about their downfall. While it’s an interesting exploration of the Doctor’s morality—particularly how, as an eternal being himself, he relates to more ephemeral living creatures—it doesn’t feel satisfying from a narrative perspective. It’s like the conclusion to a much longer story that never actually unfolded.

The pacing feels rushed, with the story ending before it’s really had a chance to start. The villains are little more than caricatures—sneering, high-society types with great power and little morality—but they’re not given any depth or complexity. Similarly, the Doctor doesn’t really develop in any way here; he’s simply the character we already know.

That said, there are some exciting moments scattered throughout, but overall, the story falls flat. It could have been much more than it is.