Overall, meh.
Things I liked:
Fudging with the opening credits.
The minute Clara said she was the Doctor I hoped they would do exactly what they did, swapping Coleman and Capaldi's names and showing her eyes. I howled with delight that they actually did it. Well done. No, the whole point of it didn't really matter to the plot (very little in this episode did, really) but it was a hoot nonetheless and worth it for the gag.
Fudging with the end credits.
Same thing here. Entirely unexpected and a fun way to tease the Christmas special.
Danny's speech before leading the Cybermen away.
I think someone upthread was right suggesting that the story was planned well in advance to coincide with Remembrance Day and Veteran's Day and Danny's speech at the end was a rousing and wonderful way to honor all the fallen soldiers who have given their lives for our freedom and our ability to sit here on these message boards and rant and rave and praise these shows we love. It was a fine idea for an arc, if executed poorly, but the resolution makes it worthwhile for me. Well done, Moffat and crew.
The Doctor skydiving into the TARDIS.
I don't have a problem with the TARDIS somehow surviving an exploding airliner. I'm still fuzzy on how the Doctor didn't get incinerated along with everyone else on that jet, but it was pretty neat seeing him skydive toward the blue box to save his skin a la Roger Moore in "Moonraker." Cool visual, if slightly unearned.
Capaldi's performance.
As noted, Twelve doesn't do anything in this episode except run around and look confused. Not a fan of that kind of "action" for the series lead. But Capaldi still found a way to make it interesting and to keep me engaged.
Michelle Gomez' performance.
I kind of hate that she's the Master because I feel like the Master had a perfectly fine resolution in "The End of Time." I hate even more that almost no explanation is given to how she came back. which I feel like would be one of the most obvious things to resolve after last week's cliffhanger. All the more so since Moffat has her vaporized in the end. Why the hell should I care then that she's back?
The Brigadier coming back, saving Kate.
I know some people find this distasteful but I was pleased that Kate didn't die and even more touched that if anyone else was going to be able to overcome the Cyber programming it would be the Brigadier. I do think it's rather tasteless and insulting to the character that they were so ambiguous about what happened to Cyber-Brigadier. Upon first viewing, I assumed he just rocketed into the sky to blow up along with the rest of the Cyber-dead, but I could see Moffat leaving that door open and I think it cheapens the Brigadier entirely to do so. Here, it was a lovely tribute and a heartwarming realization that he saved Kate's life. Anything more would be too much.
Things I didn't like:
Lazy writing and the utter and complete lack of logic.
Starting at the end: How on God's green earth did Danny send that Afghani kid back if their consciousness had been uploaded to the Time Lord cloud? Would the boys body not have been rotting away in a grave somewhere in Afghanistan? How did the kid get his same body back? How is it that the body had not decomposed to mush and dust? And how did it get transposed to whatever after-afterlife Danny went to?
What are the implications for Missy's downloadable dead? Did this apply to everyone who has ever died in the history od the world? Are they all Cybermen in waiting now? Or did those who were uploaded all fly away in to the sky to self-destruct? Did the Brigadier also self-destruct, or is he now condemned to an afterlife trapped in a Cyberman body? Most importantly, does this now mean that everyone who has ever died in the history of the Earth is actually sitting around somewhere waiting to be resurrected? Filed away into some Gallifreyan iCloud device? Moffat seems to have no problem posing these big, far-reaching questions but shows no effort or interest in resolving or answering these implications.
More importantly, what does this mean for anyone who dies going forward in the Doctor Who universe? It effectively negates anyone being killed because we know now it's entirely possible (if however difficult) to resurrect someone, even someone who has been long dead (vis a vis the Afghani boy.)
How come Captain Jack Harkness never once mentioned this "afterlife" all the times he died?
Still no resolution for why Clara was in such a fit at the beginning of "Dark Water" when she rang Danny. Like others, I expected her to be showing a baby bump when she stood up to hug the Doctor goodbye at the end. Sloppy, lazy writing.
Moffat confirmed in the iTunes extra behind the scenes supplemental video for "Death In Heaven" that we shouldn't be too invested in the Master being gone for good given how he used to get killed at the end of every serial he appeared in only to return with some blase explanation of "I escaped!", so I doubt any of us are going to be surprised when she returns. It's Spike in the
Buffy finale all over again. Big flipping deal.
In all, basically a groan-fest. More of Moffat's slow-burn for 40 minutes and then whatever tired twist he thows out in the end. Here's hoping the Christmas special is good (well, as good as the frothy Christmas specials can be) and that there's more of a return to form in Series 9.
Dear Steven Moffat,
Don't blink, don't breathe, listen, don't think, don't cremate me. And last but not least, don't write anymore shitty episodes.