I love these kind of blended AUs, in which we get to see "what would have happened if..." worlds but at the same time see the tie-ins to the world with which we're familiar. Snape's focus on Harry remains unnervingly keen in whatever narrative/world they are in, even if his feelings may be far more obviously warm this go-round. I liked that Snape's explanation for the talking castle was merely Harry's repressed memories and thoughts, whereas the walls *did* seem to speak to them both in the course of the story. And the memory for Snape's Expecto Patronum, very moving indeed.