Let’s start with the big-picture stuff. The Timeless Children was fun to watch, but more than that: fascinating. It’s full of interesting ideas, and they all pretty much make sense. The rewriting of Time Lord history accords well with what we have come to learn of that race’s mendacious tendencies, and the Doctor’s discovery of her own pre-Hartnell history makes perfect sense.
The Master’s role is crucial, his plan truly horrible; the Irish policeman’s story from last week plays into the big reveal in a perfectly cromulent way; and the reappearance of Ruth Clayton from Fugitive of the Judoon was welcome and not overcooked. I particularly liked how everything she said was reflecting back to the Doctor things she already knew.