WOW WOW WOW
That was utterly brilliant and worth the wait for the most part, easily one of the best episodes of Doctor Who since its return. So is John Hurt, the Valeyard? as that name was mentioned in the episode and all points kind of lead to him doing something terrible. Also Hurt is not going to replace Smith but since all life cycles do age eventually I assume he could easily be an aged version of the 12th cycle.
I love how Clara was put into all the old Doctor Who footage and how she came to be the impossible girl was simply awesome