That was a very solid episode!
My only complaint is the mummy bit... if the girl knows everything how did she not know that the mummy was a fake-out? or that the god was the huge freakin' sun?
What episode was the Doctor referencing when he said he's seen a universe created at the whims of a madman? The only thing I can think of is "Castrovalva", something about the Master creating a new reality and trapping the Doctor in it, something like that?