I think your enjoyment of this episode is pretty much dependent on how interesting you find the TARDIS. If you're a fan of Sexy, then there was plenty of good stuff to gnaw on. Outside of the TARDIS stuff, the story was slightly spoiled by the occasional plot contrivance, and an underdeveloped secondary cast, but had some undeniably great moments. And I'm not just talking about Jenna's dress.
For once, I'm not going to complain about the monsters or the CGI. When I first saw the out-of-focus space zombies, I admit, I face palmed and thought 'Oh man, they look just like men'. When it turned out they actually were just men (and one woman), my complaint suddenly seemed redundant. Plus, the CGI was at times beautiful: particularly the heart of the TARDIS, the architectural reconfiguration system (I'm going to call is ARS for short—and secretly lament that they couldn't find an E word to make the acronym perfect), the spilled encyclopaedias, the Eye of Harmony, and the TARDIS' magnificent library. (Oh what I wouldn't give to browse that.) Kudos to The Mill for doing arguably their best work on the series to date.
And while we're on the subject of contrivance, this feels like the perfect time to mention the tiredest plot device known to man—the reset button. I should have experienced at least some disappointment at them rolling it out, but it was so perfectly telegraphed, and so humorously woven into the script, that I can't bring myself to complain. Since the episode opened with a meta gag about how handy a 'big friendly button' would be, it seems only fitting that it should resolve itself with a reset button style ending. There was even a degree of logic to it: the reset button was the magno-grab's remote, 'found' by the Doctor in Gregor's pocket, and then thrown several times through the time rift.
Of course, the reset button style ending meant that virtually all the cool stuff which transpired during the episode—Clara seeing the Doctor's name in 'The History of the Time War', the timely reveal that her and the Doctor are better acquainted than she thinks—was essentially redundant. Or was it? Despite having no recollection of his TARDIS adventure whatsoever, Gregor still managed to exhibit signs of a changed attitude towards Tricky. How are we to explain that? If all that Gregor experienced during his TARDISapalooza was expunged from memory, then why the change in his character?
Sadly, the Van Baalan brothers didn't have enough air time to make their mark. Bram died a dumbass' death for ignoring his younger brother's advice to keep away from the TARDIS' console, and Gregor was pretty much unlikeable from the get-go. I get that he was in the salvage business, but was taking a cutter to the TARDIS' ARS(e) really the most sensible option? He didn't even know what the machine was. How did he know where to cut, or that stealing one of its globes would do anything once he'd returned to his ship? Tricking Tricky into thinking he was a robot, also felt a little cruel. Yes, it helped us sympathise with the younger brother (and provided something of a twist), but it also meant I spent half of the episode hoping Gregor would die horribly.
But these are fairly small gripes compared to the stuff which did work. Clara meeting up with herself, her attempts at communicating with the Doctor's echo, and the relentless pursuit of their zombie selves, were all effectively done and spectacularly odd. Clara really is starting to feel like a proper companion now. She spent the bulk of the episode having to fend for herself, she managed to outsmart her malformed future self (at least for the most part), she dashed down corridors like a champ, and she even managed to discover something new about the Doctor. Not too shabby for a beginner.
And now that the Doctor and Clara have finally come clean with each other about what they know, it feels like a new trust has been forged. I think the hearty hug came as something of a relief for both of them. Secrets can function as a protection, but they can also impede trust. The question is, will any of this new knowledge stick now that the reset button has been pushed? Obviously the Doctor will continue to remember, but what about Clara? Is it possible that everything Clara learned deep within the bowels of the TARDIS will bleed through again at some future juncture? I certainly hope so.
—I couldn't help but smile at the Doctor shaving 30 minutes off the time allocated to save Clara. That pretty much cut the available rescue time down to the length of the remainder of the episode.
—A very Red Dwarf style beginning.
—Two cloister bells ringing in two episodes? Poor Sexy.
—The music for tonight's episode was dire. Half the time it just didn't belong. I tend not to notice the music too much. I'm of the opinion that a soundtrack should enhance the action without being particularly noticeable, but tonight I was noticing it all the time—and not for good reasons.
—I wonder who wrote 'The History of the Time War'. And how lucky was Clara to stumble upon the Doctor's name almost immediately?
—Lovely 360 degree rotation around the TARDIS' console.
—So many sound-bytes from past episodes. I caught snippets from 'The Robots of Death', 'Rose', 'The Doctor's Wife', 'An Unearthly Child', 'Smith and Jones' and 'Colony in Space'.
—'Lancashire' and 'sass' pretty much sum Clara up.
Doctor: 'Don't get into a spacesuit with a madman. Did nobody ever teach you that?'
Clara: 'You're not getting me to talk to your ship. That's probably bonkers.'
Doctor: 'I can feel a TARDIS tantrum coming on.'
Clara: 'So that's who!'
Doctor: 'Smart bunch, Time Lords. No dress sense, dreadful hats... but smart.'
Doctor: 'Okay, so we're not doing hugging. I get that now.'
Doctor: 'Secrets protect us. Secrets make us safe.'
Clara: 'Were not safe.'
Doctor: 'I brought you here to keep you safe, but it happened again. You died again.'
Four moor peaces eye rote, sea hear.