It was nice to see a (tiny) little more of Paul McGann.

All this just makes it sooo confusing....

So now there are two incarnations of the Doctor that don't use up a regeneration?
That's like cheating.
Between 8th and 9th we have John Hurt's "War Doctor", and between 12th and 13th we have the Valeyard. But neither of them use up a regeneration just because they don't want to use the name "Doctor".
Or does this really mean that Hurt's Doctor is now retconning the numbers, making Hurt number 9, Eccleston number 10, Tennant as number 11, Smith as number 12, and Peter Capaldi as number 13? And what of the Valeyard? He was real, not a ghost like the Watcher... so surely he's the 13th Doctor, and Capaldi is actually the 14th?

They should have made out that Hurt's "Doctor" WAS the Valeyard, which would have been between Smith and Capaldi, and made it the correct numbers and order of the Doctors in the end.
Moffat's creation of the War Doctor has messed up the chronology of the Doctor's regenerations... just for the benefit of one episode. And I thought he was a fan, so should have worked that out better, instead of retconning what already existed.

I hope there are some other diehard DW fans out there trying to figure it out to force Moffat to sort it out... or maybe something in tomorrow's episode will make some sense of it.

Speaking of tomorrow - from the commercial on TV, could tomorrow's episode be loosely referred to as "The 4 Doctors", as it will include 8 (Hurt), 11 (Tennant), 12 (Smith), 13 (Capaldi).... but not all four at the same time though.