One of the things I liked about "The Time of Angels" was how SFnal it was. It was jam-packed with SF ideas-- not particularly original ones, but they were there, overflowing. Too many ideas for the space. Ideas that were just there as world-building, and not there to be explored. Though some of them might yet be clues to the solution. Moffat has made his rules for storytelling clear to us, in "The Belly of the Beast", when the Doctor told Amy to look around and observe.
In the context of this messy world, which is larger than the story itself, we see River Song, another mystery. We know where she ends, but we don't know where she begins. We're seeing the Doctor's timeline with her, but not her timeline with the Doctor. We're getting that backwards. She's confident and informed. The Doctor is off-balance and ignorant. This is a reversal of roles for him, and delicious to watch. (Too much strutting and the Doctor becomes obnoxious.) Watching them together is like watching Four and Romana bicker over which one of them is better at flying the TARDIS. She is, and she proves it.
We don't know yet how River reaches this point. We're probably going to see her story out of order. Moffat has always liked the time-travel part of the Who universe, and here's another timey-wimey SF puzzle. I love it. We watch her regress, we watch him progress, somewhere they meet. Sometime after the Doctor tosses her into prison? Just guessing it's the Doctor who does that. And what a mystery that is, eh? What's her game? What's the Bishop's game? Who is she, really? I think we have no idea yet, though the clues are likely there.
Older, confident, educated, smart. She's in the Doctor's weight class, and when they meet in the ring it'll be a fair fight.
As for the baddy of the week, do I have to talk about why they're creepier than last time? Something about those worn down statues with the hollow eye sockets is worse than the clean statues with the sharp teeth. They're like the corpses of angels, reanimated.
Amy Pond is shaping up to be my favorite companion since Ace. Irreverent, clever, quick on her feet, not overly impressed by her Raggedy Doctor, but completely willing to have fun. She gets herself out of that mess with the angel on video, using the clues given her.
Then there's the scene where she thinks she's turning to stone and can't run from the angels. What would, under the previous producer, have been soppiness ("oh, I won't leave you behind!") was instead clear-headed behavior from both of them. She tells him to just go and leave her, he says no, and then he bites her hand. He bit her! How awesome was that moment? I won't miss Ten's sentimentality even for a second.
Last week's script was just filler. Dalek set up. Boring. They should have tossed it. This week was the real thing. I had no sense of time passing. When the episode ended with a cliff-hanger I was shocked and so was Mr Pedia. What? Over already? You didn't warn me it was a two-parter! And so I wait eagerly for next Saturday.