Spoilers and nerditry after the jump.
Basically, the first half of this episode was shapeless narrative searching for some kind of structure, then the story finally gets moving and we get the Master turning the entire population of the Earth into himself -- AWESOME.
And we get the impending return of the Timelords (!!), which parallels the conclusion to "The Waters of Mars" surprisingly well -- in that previous episode, the Doctor, at the end of his patience at being a fatalistic witness to tragedy, briefly gives up his ideas of responsibility and tries to reshape history itself because he's the Last of the Timelords, dammit. Of course, he sees the dangers of what he did (ignoring, for the moment, the consequences of tampering with history that we saw in "Father's Day") and rediscovered his sense of Gallifreyan morals, perhaps because he's not the Last of the Timelords. On the other hand, the Timelords we see at the end of "The End of Time, Part 1" don't seem to share this same sense of duty, for they are spitting mad...
... and much like the mad-Doctor at the end of "The Waters of Mars," seem intent on bending existence to their wills.
A reference to the Weeping Angels from "Blink"?
Indie rating: Acid Mothers Temple & The Melting Paraiso U.F.O. – In D