"Previously on Doctor Who ... 709 episodes ago" XD
Wait, wasn't the first appearance of the Cybermen also the last serial of the First Doctor? So both Doctors in this ep are about to regenerate!
Ooh, nice transition! Wait, so Twelve just arrived in Antarctica? Brb, rewatching The Tenth Planet.

...

Okay I'm back and now I'm wondering when this episode is set. Between One going to the TARDIS and Polly & Ben arriving at the TARDIS?

Let's finally continue 11x00.
New Polly's hair looks so fake. And they got the hairstyle slightly wrong.

Ugh, you know what I'm not a fan of at all? When something someone did turns out to not have been done on their own. Like in Life on Mars, when adult!Sam tells his mom what to tell kid!Sam about where his dad is. I mean, come on, as if she couldn't think of something herself! And here we have One not wanting to regenerate and Twelve having to talk him into it.
And time stopped - so that's how they manage to squeeze a previously unheard-of adventure between scenes of an old episode.
Wow, what a resistant little snowflake!
"Maybe it's us. Maybe it's something else. But somehow something has gone very wrong with time." Uh, "something else"?!? Dude, there's your earlier you refusing to regnerate, thus about to make you unexist - I think it's safe to say that it's you two.
"Are you trying to be funny?"

Oh dear, the German's German is a bit hard to understand.

What's with One being so sexist? As far as I remember he wasn't.

Bill! \o/
Ugh, now she has to explain to the unconviced Doctor that she's the real Bill! What, he didn't have any problem accepting people in similar cases!

I'll never get over this alternative usage of "time zone". Forever petpeeved.

Aw, we get to see the old TARDIS again.
"I said that!" - "Same difference."

Villengard? Wasn't that a place that the Doctor mentioned to Jack in the The Empty Child two-parter? I think he said something about having destroyed the weapons factories. Since that was in Moffat's first eps and this one is his last, that's a quite bookends!
Was that a Dalek without a shell? Hee!

What, so that's really not Bill? Or has she become a water creature like Heather? Because the first time we were shown the water woman, I thought it was Heather.

You can't just play a version of Doomsday, think of my feelings!

A good Dalek \o/! I always wanted to see one of those. Although that Dalek doesn't quite fulfill my expectations.

Ooh, New Earth!
I'm so glad that's the real Bill. Would have been such a disappointment if it wasn't.
My god, Moffat with his non-death deaths! First the Library, then Clara, Missy's Nethersphere thing, Bill and now Testimony. I mean, it's a cool concept, but it's getting a bit repetitive. At least that should be over now.

Bill still has to defend her realness to the Doctor, argh! It's getting offensive. Are they looking for a reason why Bill won't travel with him again or what is this about?

The Captain is the Brig's dad or granddad!
I don't like that his request could mean that the Brig and the Doctor didn't meet by chance. Though if Twelve didn't remember meeting the Captain (going by his surprised look), One probably didn't either.

Aw, German Christmas carol.
So how did the Doctor manage to adjust the time frame? How did he move those soldiers a few hours into the future?
What, has the Doctor really saved the Captain? I mean, he's still in a war and could get killed there.

I don't like that they made it look as if Polly & Ben didn't come into the TARDIS before it took off.

"You know what the hardest thing about knowing you was? [...] Letting you go." IT'S SO TRUE! Twelve is my second favorite Doctor. I don't want him to go!
"Letting you go is so, so hard. Isn't it?" How very meta. I swear this question isn't aimed at the Doctor but PCap.
OMFG, the Doctor still doesn't believe that this is the real Bill. Is that supposed to be funny?!

I still don't care about Clara, but it's good that the Doctor has his memories of her back. How the fuck was Bill able to do that, though?
Huh, Nardole also joined Testimony. Why do I feel so "WTF ever" about him? I mean, I don't even dislike him, but I just don't like him either. He's just... there.

Aw, the TARDIS talks to the Doctor and convinces him to regenerate.
But why don't eat pears?!
Jesus Christ, this is going on forever! Stop dragging this out, it's bad for my heart!
Whoa, he shouldn't stall regeneration and then stand to close to apparatuses! He's damaging the TARDIS again. Which means they'll change the interior again, meh.

So how do you regenerate into a bottle blonde with roots? If you can do that, surely you'll manage to regenerate into a ginger!
"Oh, brilliant." ♥
Whoa, didn't expect the TARDIS to crash again. Even more similarities with the Ten-Eleven regeneration.
Aaand there end the similarities: I really didn't expect the Doctor to fall out of the TARDIS. Geez, you don't have to make her regenerate again so soon! Oh, no, wait, question solved! This is exactly how she can survived, because she only just regenerated! For a few hours she can heal without having to regenerate into someone new.

In conclusion:
- The plot was a bit thin.
- Better than your average Christmas special, but still not really good.
- I want to see more naked Daleks!