I can't resist; I'm skipping to the end of the episode first.
I did not see that coming. So the little girl's a Time Lady? What the hey?! Who is she then? Is she Amy's daughter who was somehow born as a Time Lady because she was conceived in the TARDIS? (I'm assuming Rory is the father. Surely Steven Moffat wouldn't have Amy impregnated by the Doctor.... Would he?) The Doctor's medical scan of Amy at the end of the episode seemed to imply that Amy's fetus is already jumping in and out of time (or in and out of existence), which might be totally normal for Time Lord babies, who knows? Or is the little girl a young River Song, making that shady dame a secret Time Lady all this time? Maybe River was the Rani in a previous form. Or Romana. Or, a little more outlandishly, the little girl could be the Doctor's granddaughter Susan who hasn't been seen since the days of the First Doctor. Or maybe she's the Doctor's cloned "daughter" from a couple of season's past having regenerated from Georgia Moffett into a little girl? Or perhaps she's a combination of these possibilities. Perhaps she's Amy and Rory's TARDIS-conceived Time Lady daughter who just happens to grow up to become the Rani who later reforms and becomes a certain benevolent Doctor Song. Nah. That would be too confusing! There is one other possibility. Perhaps the child is the daughter of River and the Doctor. Remember last week, River also got sick after forgetting the Silents, just like Amy did. Does that mean that River's pregnant, too? We know from the ending that River and the Doctor had been quite intimate in her past (but his future), so if she is pregnant, that'd mean the baby is at least half Time Lord. Hmmm.... In any case, the possibilities have my mind reeling - and have me excited, waiting for answers.
So, aside from the ending, how was this episode? In a word, great! Continuing on from last week, this episode contained even more creepy stuff - Amy, Rory, and River marking on their skin how many times they had seen the Silents, the abandoned orphanage with the ominous warnings (written in blood?), the Silents hanging from the ceiling like bats, the Doctor imprisoned and looking like an unkept crazy person, Amy's disembodied voice begging for help through the communicator, and so on. If I were a kid, I'd have definitely been hiding behind the sofa for this one. I also thought the Doctor's solution to the problem of the Silents (involving a phone camera, Neil Armstrong's boot, and the televised moon landing) was creative and clever - although I am rather surprised that the Doctor would inspire humans to kill off an entire race of aliens, no matter how evil those aliens are. Actually, there was rather a lot of violence in this episode (what with River and the Doctor blasting Silents with guns and screwdrivers), which would probably be the one negative thing about the episode for me.
As with many of Moffat's episodes, the script answered a couple of minor questions but left many of the bigger questions to linger while introducing a few new wrinkles as well. As I mentioned above, we still don't know who the little girl is. And now we have to wonder about her status as a Time Lady, too! And why, exactly, did the Silents need her? And why did their ship look like a TARDIS? Also, we do not learn why the little girl (if that was her in the spacesuit at the start of last week's episode) killed the future Doctor - or why he allowed it to happen. And what was with that lady with the metal eyepatch who peeked at Amy through a peephole in the door and said, "She seems to be dreaming," only to then disappear (along with the peephole)? That was like something from a bizarre art film, and I have no clue where that's going.
Overall, I'd say this is the best opening for a Doctor Who series in the modern era. I'm really digging the scary yet funny tone and the various mysteries have me begging for more. I must admit that I am a little concerned about next week's pirate-themed episode, but I'll go into it with an open mind hoping for the best.