TV With my attention elsewhere, I've only just caught up with this. As usual ...
(1) Capaldi sounds like the Doctor. Properly the Doctor. He seems like he's finally realised how to play it and his line readings are on point.
(2) Claire Higgins returns as Ohila from The Night of the Doctor as a representative from the Sisterhood of Khan. Note that it doesn't actually feel the need to tell us who she is and who they are because it knows we've watched the Eighth Doctor's regeneration story.
(3) Speaking of which, "Look after the universe for me. I've put a lot of work into it." was another Twelfth Doctor's final line - the Hugh Grant incarnation from Curse of the Fatal Death (though the canonical Eleventh used a version of it in his first adventure). Note how Capaldi says it somewhat ironically.
(4) Isn't that the same rock face that appeared in The Time of the Angels? It'll be a repurposing but it's nice that they've branched out from reusing Peace Hall every week.
(5) Who is this enemy? Clearly we're briefly supposed to assume it's Missy, but the pronouns are all wrong now. Is it Sabbath? Rassilon? Borusa? As earlier or later incarnation of himself (and wouldn't it be refreshing to have himself as an antagonist) (depending on your opinion of the Valeyard).
Either way, along with the feature in this month's edition of the parish circular and Last Christmas, I'm much more positive about this next season that I was at the close of the last.