The lighting was absolutely stunning; I was impressed with a lot of it (the acting, the casting, the script) but the lighting was the part that is still making me go WOW two days later.

I do have to say I winced at an As You Know Bob fairly late in the episode, when they made Gatiss (who I agree was excellent) drop some info about the Holy Roman Emperor then say something like, "Oh, I see your boy doesn't understand." and explain why that was important. I was like, "okay, by 'your boy' you clearly mean 'the audience', but surely the set-up for Political Motivation Exposition could have been a little less OKAY IT IS TIME FOR EXPLAINING NOW"