I like a lot of this episode, but I will say this: I'm beginning to fear, after two episodes, that they're making a misstep with Capaldi. The guitar/tank goofiness, the sunglasses - he's a bit different to last year, essentially a bit more Tennant/Smith-ish - I assume a reaction to some of the negative words on his attitude from some fans and press, especially in the UK where some papers pegged it to the ratings slump & said he was too old and grumpy - but I'm starting to get the feel (admittedly only two episodes in) that it's diluting some of what made him so fresh and magnificent last year. When he was allowed his darkness in these stories he really shone, and I hope he's allowed to fester in that more in the coming weeks.
PS: I'm really hoping this 'what did you really flee Gallifrey for/confession dial' isn't this year's 'arc'. Can we have an arc again that isn't all specifically about the universe revolving around the Doctor? Every year -- his prison, his death, his death again but now with a secret -- and then anything with the Master is always about 'them' ultimately; S3 was too. I yearn for something disconnected from him like planets disappearing from space that he stumbles into again.