• The inner mechanics and workings of the Dalek were really interesting, as was their limited vocabulary, but it makes the Daleks themselves seem less hateful than the machines they're cased in forcing them to be that way that doesn't seem to mesh. It also doesn't feel like it matches with the setup we saw with Soufflé Girl - although admittedly that was more specifically brainwashing, but the communication limitations seems like they'd have impacted things there.
• Missy & Clara's interactions are really interesting, and while some of them are fun and have the whole cat-playing-with-a-mouse vibe to them, and have interesting little playful dynamics with Missy talking about the Doctor or their own past, sometimes the things in her dialogue feel a bit too… scripted? forced? I get that a lot of that comes with this Regeneration's mannerisms, but sometimes it's a little much that pulls me out of their current dialogue, but the rest of the time it's incredibly engaging -- I also really hope that (given that she's exiting this season) that we get to see why Missy sent her after 11 in the first place and by doing so, set off the whole Impossible Girl scenario.
• Colony Sarff is properly creepy and terrifying and I enjoyed it as a creature, but sometimes its use seems… strange? Like the final play to have the snakes use themselves as a power conduit seems less-than-logical, and given that it wasn't shown that they were anything more than normal snakes, it seems a bit out of left field.
• Wearable Tech. I really dig 12 in the sunglasses, and it echoes a bit of 10's 3D glasses mannerisms, but I'm not sure about it as a Sonic Screwdriver substitute.
• Hints about a hybrid prophesy. While I am interested to see them explore the Doctor's motivations about the TARDIS stealing him away and him constantly running (props to Capaldi's acting again during those bits) the possibility of a Dalek/Timelord feel too StarCraft II for my tastes, though depending on if that's misdirection or how they play it out, it MIGHT not be terrible.