As Christmas episodes go, a nice bit of holiday fluff and not much else. Enjoyable, but I can't see it being especially memorable.
Nice happy Doctor to start with, grinning to himself as he surveys the snowy scene of people milling around and enjoying themselves. Obviously it's not immediately after he lost Donna. He looks even happier, though, when he hears someone calling Doctor! He's all ready to jump into the fray when suddenly someone else comes up and introduces himself as the Doctor. Cue momentary confusion, and then delight as he jumps to the conclusion that this man is him in a future regeneration. Interesting how happy he looks to see a future him. Loneliness setting in so badly that he's actually glad to see another him?
Of course, we all knew all along - didn't we? - that Morrissey wasn't actually the Doctor. The explanation for his belief that he was the Doctor was nicely done and fairly credible, though I did wonder why the Doctor believed him - wouldn't he have sensed that Jackson (Morrissey) wasn't a Time Lord? Clearly, he knew from the moment he used the stethoscope, and I think his manner towards Jackson changed a bit after that.
Cybermen... another repeated enemy. Ah well. Ms Hartigan made a different villain, which was nice for a chance, though I really would have liked to find out what made her so driven to achieve revenge. Bit of a loose end there.
Morrissey as Jackson I liked. Nice character, well-acted, and I was glad that he turned out not to be a bad guy but an ordinary good guy being the Doctor because he believed that he had to be, fugue state or not.
And as for the Doctor, in the end not as carefree as he liked to pretend. Again, he's throwing himself into situations - yet another hint of not entirely caring if he lived or died at one point, I thought, when he sent Jackson away to be safe and ran after the Cyberking himself - and making friends in an instant. Jackson got rather more in the way of confessions than most people do with that line at the end about companions:
"All those bright and shining companions... but not any more?"
"No."
"Might I ask why not?"
"They leave. Because they should. Or they find someone else. And some of them... forget me. I suppose in the end... They break my heart."
Oh, Doctor. It is good to see the nod to recently-departed companions; Donna's not forgotten, nor is Rose, or Martha. Possibly Sarah-Jane and Jack as well, though that's up to interpretation. Though I don't want angsty Doctor for evermore, I don't want him just ignoring everything he's just lost either. For me, that short exchange with Jackson at the end was the best three minutes of the episode. And a hopeful ending: he actually agrees to stay for Christmas dinner. But still... is this why no full-time companion for the specials? Because he doesn't dare open himself up again?
One more little touch I liked: the infostamp with images of all ten Doctors to date. Including Nine - yay!
And, from a purely selfish point of view, this episode does mean that my post-JE WIP isn't Russelled... yet ;)
Marks out of ten - perhaps seven, as it was definitely watchable and the costumes were very nice even if the fake snow was very... fake ;)