This one surpassed many of my expectations.
First of all, after three stories we finally get more hints for the puzzle.
Second of all - yes yes, David Tennant is here and he is great, but that's not him I was so excited about. Not him, but Stephen Noonan as the First Doctor. I was worried that the original three might not get time to shine, yet I'm actually happy that the First Doctor (one of my favourites) was in the beginning of this story and leading the plot for some time. I was sceptical about Noonan's performance at first, but after this one I can safely say that he is amazing as the First Doctor.
Missy... she is wonderful. I didn't get to her in the series yet, but she is glorious and I can see why people love her so much. And the reveal about her part in this anthology was also great.
The Paternoster Gang was really funny here, all of them got time to shine. And the original character Jesamy Moore was interesting, although she kinda fell into the background near the end of the story.