Key element - remove the Doctor from the picture. It's like the early days of the show, when the Doctor was exiled on Earth - remove a normal element of the show and see how things play out.

A bit of a wrap-up, as well, for the angst Clara has been facing regarding decision-making, lamentable deaths, etc.

Really, really well done.

The trees one just annoyed me with the way it utterly ignored basic things like fire behavior and the ability (or lack thereof) to remove oxygen from a small, uncontained space. The final bit about oh, don't worry, you'll forget all about it - cheap cop-out (though I did quite enjoy the Doctor's like that if humans didn't forget, they would stop having wars - and babies.

The finale, though was great. I didn't notice the cyberman eyes pattern until the double doors. Despite all the trailers (assholes) showing cybermen, I didn't twig to cybersuits in the water until the double doors appeared - then it all became clear. Love the idea of a now-female Master putting the lip lock on the Doctor whilst pretending to be a robot. The Doctor is going to have to scrub his brain with bleach to get rid of that memory.