Based on the trailers, this was the episode I was probably least enthusiastic about, but it turned out to be much better than I expected, unlike Praxeus, which looked great in trailers.
I think this would have benefited from a longer running time, there were some awesome concepts, and some truly great visuals, with more time to develop this would have worked much better.
Stunning visuals, this episode looked fabulous, how much of the budget was used here, this truly was impressive to look at. I liked that we had an introduction to the story before the opening credits. An excellent villain, and secondary villain. I found myself reminded somewhat of Amy's Choice, with the Dream Lord, and Enlightenment, but that's no bad thing.
I loathe the TARDIS interior, I would expect travelling through time and space with those lights they'd all have headaches, the interior they introduced for the new Doctor in the Judoon episode was amazing, this one really is a mess.
The Doctor's reaction to Graham's cancer was poorly judged, The Doctor has ways been awkward, but always cared about humanity, and companions, this scene was badly written.
A visual feast, with a very good menace. Thought this was rather good. 8/10