Well, bother. I really should have been a smart-arse and mentioned my theory about River Song’s identity, because I was 110% right. There was a hint I’d picked up on in an earlier episode which did indeed turn out to be the relevant one. And I won’t say any more about that until tomorrow to allow for people watching later.
But yes, that was big, bold and featured lots of old friends. Big bangs, big fights, lots of action, lots of misdirection, and lots of tying in to the events of the opening two-parter. And of course, suitably cliffhangery, as expected, though more of a “please resolve this storyline” cliffhanger than an “oh noes, how will they get out of that” one. Which is probably just as well, because the next episode won’t be on until September.
Oh, and according to the caption at the end, that next episode will be called “Let’s Kill Hitler”, which sounds like a bit of wibbly-wobbly, timey-wimey stuff.
More on this tomorrow, or thereabouts.
 Apologies to any crazy furriners reading this, I know that you may be a week or two behind, so this site will not be a spoiler-free zone for you.