Oh, sad but also hopeful. Amy and Rory can't get Melody back, but they still have River, and they have to figure out how to keep that relationship with the knowledge of what came before.

I loved this line: Time in reverse doesn't offer pre-built relationships, just delivers their precarious frame, the shifting ground on which to find and hold a balance, clinging by fingertips.

And I think I see a nod to your other story about the swingset too... River apologizing for not being able to open up to Rory and Amy then, having to keep herself always guarded even as a child. Well done.