I'm not quite sure what to make of this episode. A lot of it reminds me of "The Beast Below", meaning the alien marketplace set, the kid in distress, the new Companion saving the day instead of the Doctor. I hate it when Moffat recycles stuff. Can he not come up with anything new? On the other hand, there were moments I liked that made the episode worthwhile. And so, swiping Jayne Gudkov's format once again, here I go...
WHAT I LIKED
The Doctor stalking the latest incarnation of Clara through time as he tries to figure her out. His exclamation, "She's not possible!" revealed his frustration upon realizing who and what she might really be. It conveys once again that, as usual, the Doctor is several steps ahead of everyone else.
Showing how Clara's parents met, establishing before our eyes that, yes, she is — at least on the surface — pretty much what she appears to be: a normal human woman. That this stands in stark contradiction with what the Doctor might or might not know about her only adds to the mystery surrounding the character. I like a good puzzle!
The TARDIS doesn't seem to like Clara, much as it doesn't like Captain Jack Harkness (who is a fixed temporal "fact" because of the actions of Rose Tyler in her brief time as the Bad Wolf entity). The reason for this might seem obvious: this is a woman who has existed with the same body and name at three different points of space and time, for reasons yet to be revealed. The TARDIS, being temporally aware of the past, present, and future, knows who and what Clara is even if she and the Doctor don't. I can only guess, but she's got to be the product of an entity similar to Bad Wolf, possibly even Bad Wolf herself. Think about what the entity is capable of: fixing things and people throughout space and time as a message to the Doctor and her past self. Why wouldn't this be something along the same line? Is it possible that Clara or someone who knows her somehow morphed into Bad Wolf II by absorbing energy from the Time Vortex, just as Rose did, and orchestrated the events within the story by replicating Clara throughout time and space? If I'm right, it's Moffat recycling things that have already been done in recent memory, and it's a huuuuge cheat for which he may never be forgiven. On the other hand, depending on how it plays out, it could be epic. We'll just have to wait and see.
WHAT I LOVED
That whole speech toward the end where the Doctor tells the monster about everything he's seen and experienced. Matt Smith revealed again just how awesome a choice he was to fill the role. I couldn't help but get misty-eyed.
WHAT I DISLIKED
You just know I'm gonna have problems with anything in a show run by Stephen Moffat, but this one is (relatively) minor. When the Doctor and Clara rush to an asteroid-based pyramid to save a little girl, they take time out to buy a space moped instead of using the TARDIS. HELLO! I understand Neil Cross, the writer of this episode, wanted emotional moments, such as Clara having to trade her mother's ring for the moped (the people on this planetoid use things that have sentimental value as currency). But really, this whole not using the TARDIS just because it makes things more difficult for the Doctor and Clara and allows the excuse of making the episode longer, doesn't work at all. Shame on you, Moffat, for letting this plot point be used.
WHAT I HATED
The smiley face on the monster gas giant. LAME. That Clara and the Doctor essentially snuffed out the star or "mother" planet around which at least seven inhabited worlds orbited and it had no apparent devastating effect (thanks, Jayne, for pointing that out). That, in defiance of the laws of physics and what we know of the vacuum of space, Clara and the Doctor are able to ride a hover-moped through space with no protection from the vacuum of space whatsoever and not freeze or die of asphyxiation. It is unforgivable that a science-fiction show completely ignores good science, and presents horrendously bad science, so frequently. Come on, people! You can do better than that!
QUOTES FOR THE WATERCOOLER
The Doctor: I've seen bigger.
The Doctor: Are you joking!? It's massive!
"Cold War", featuring an Ice Warrior on a nuclear submarine in the 1980s. David Warner guest stars.