There are so many things that stand out here.
1. Foxes performance of the Queen tune "Don't Stop Me Now." This was just stunning.
2. Clara, who is one of the hardest companions to like, becomes a little more likable, and her flapper dress makes her one of the best dressed companions ever.
3. The wonderful nods to Doctor 1 and 4. Loved Capaldi's tie as well as his cigarette case of jelly babies.
4. The honesty that you get from 12 at the end of the episode. This season has several arcs going on, but one of them involves the Doctor finding out if he's a good man, and in this episode, I think he proves that even though none of the choices he could make are good ones, he still does his best to save people. He's a good man.
5. The mummy. This monster is really and OMG kind of scary. The way it walks definitely, with the toes that bend under with each step. Shudders....much scarier than the spider/bacteria thingies from Kill The Moon.
6. Frank Skinner as Perkins. Ah....he was a little bit snarky and a whole lot of fun. I wish he would have taken up the Doctor's offer to travel with him. Anyone else out there think it would be fab to have some companions on the TARDIS that aren't boyfriend/girlfriend types?
7. 12's taking on Maisie's emotions to be able to see The Mummy. This was brilliant. It also let you see Capaldi's comedic brilliance. He's a funny guy. You may not have loved Robot Of Sherwood like I did, but you have appreciate how funny it was. Not everything in Doctor Who should be serious.
8. The look of joy on 12's face at the end.
This episode was just wonderful and is one that you can enjoy over and over
Let's send out some kudos to Jamie Mathieson, because he has delivered again.
At first I though that this would be a Doctor Lite episode, since 12 was trapped in his incredible shrinking TARDIS, but it really wasn't.
Clara, has to be "The Doctor" in this episode, and though I'm not usually thrilled with shows that have her being the most important thing ever, I loved this one too.
The monsters in this one, again are really really creepy. Scary creepy. (You may want to hide behind the couch)
This is another episode filled with reasons to watch, even if you aren't a full on Whovian.
1. The whole Addams Family TARDIS thing
2. It really is bigger on the inside!!!!
5. Missy! OMG I WANT TO KNOW WHO SHE IS NOW!!!!!
Both of these episodes were strong and more importantly are ones that you'll want to rewatch.
All I can say is, Mr. Mathieson, please write more for Who!!