Not quite as good as the previous part of the story, but still a well told story that reaffirms the central creed of the Doctor.
As I suspected, all the stuff that seemed to have happened in the cliffhanger turned out to be at rather misleading... well, I kind of didn't expect [spoiler] to go that early anyway.
This was a much more talky episode - not to say that there wasn't some action. We got many scenes between the Doctor and an arch enemy, the actor playing the latter having to rely on voice acting as he was under heavy prosthetics. It did seem a bit odd that he was suddenly being all introspective and remorseful... but the fact that it was unconvincing was probably meant to be the point.
One does wonder if the Doctor having to use that isn't going to cause problems for him later; that did seem a lot of stuff to use. Capaldi had another strong episode; a bit less manic in this one, but still very much nailing his version of the Doctor. I also rather liked the flashback scene near the beginning. It seems that 'vampire monkeys' are a real mythological thing.
Clara spent much of her episode encased in a Dalek - there is a reason for this and it kind of helps that Jenna Coleman is only 5'2"; it makes it easier for her to fit insider the casing of the 'current' Daleks, which were designed around Billie Piper's eye-line. Anyway, she has another good episode, especially her many scenes with another character.
Namely, Michelle Gomez's Missy. I described the character of Root from Person of Interest, played by Amy Acker, in an earlier post as the "most deliciously crazy and unpredictable one I've seen in my life". With apologies to Mrs. Acker, I'd have to say that Missy is arguably much more crazier in this episode - using a rather unconventional method of measuring the depth of a hole for one thing. That said, Missy definitely reveals that she is on the side of the baddies towards the end of this. As such, if I had to pick between her and the computer hacker from Texas to go in my adventuring party, the latter wins hands down every time as she probably wouldn't try to kill me.
The Daleks get some very interesting additions to their back-story - it's worth noting that Moffat has officially denied a long-standing rumour about them being contractually obliged to appear in every season - and in particular, some further levels of horror added to their story.
The conclusion sees a spot of classic timey-wimey on the part of Moffat and a considerable amount of classic era invoked; one does wonder if this was perhaps over doing it.
Finally, sonic sunglasses? Well, it gives another lot of merchandise to sell, that's for sure.