THE GOOD- "Don't panic! Just one question... do you have any idea how to fly this thing?"
- On the obverse, "I will always remember when the Doctor was me" is a pretty neat ending line.
- The Christmas theme was developed well and a lot of it was pretty non-intrusive; snow, a town called Christmas, the time machine/turkey stuff were all quite fun.
- Handles was fun. I liked Handles.
- The main plot points were pretty good, the storyline occasionally got a bit obscured by jumble but it was actually a really neat underlying concept.
- Some hole closures! At last! So we now know wherefore Silence Will Fall, who the Silence really are and why, wherefore the Crack In The Wall - which is a decent record for an hour of plot point closures.
- I'd have given Matt less prosthetics for the job, but of all the Doctors so far he's the one who is best at coming over as hundreds of years old and he did it exceptionally well. The cracker-pulling with Clara was for me by a mile the most touching/feelsy moment of the whole episode; age as a theme was done well.
- The explanation of the Silence was really very neat and I liked it a lot.
- Clara had some excellent moments. Clinging onto the outside of the TARDIS was pretty neat, and dealing with the really old Doctor was good too. "Help him change the future! Do it!" was also a particularly memorable line.
THE BAD- The running nudity gag was really pointless and I didn't find it at all funny.
- Also the flirting with a sexy space Nun-cardinal. That was odd. Good character, generally, but the flirting I found a bit weird.
- Cheese scenes with Clara's family. I think having it interrupting the family Christmas was fine, and the Turkey in a time machine was fun, but the emotional scenes and continual returns to the dinner table just didn't add anything (and for tying up this many plot points in an hour the main plot could've done with more time).
- Limiting it to only one going back/finding the Doctor old would have boosted the impact, felt less powerful the second time despite that being the climax.
- Clara should steel up a bit. She spends too much time wielding sappy one-liners; I think it would have been more powerful for her emotional links if she'd simply pointed out to the Time Lords that the Doctor is their only chance of escape. Whispering "If you love him..." had a lot less impact than the emotional desperation of the previous "Help him change the future!".
- The cameo for Amy was cute but actually got in the way of the Doctor's last words and cut the power out of them a bit I felt. I think leaving the scene up to Clara and the Doctor at least so far as speaking roles were concerned would have worked better.
- Starting Capaldi off with a zany kidneys line? We already played the "Ooh, new body bits" game with Smith.