/Somewhere along the way, he becomes a mad man with a box./ - Oh, of course. Mirrors! How did I miss that?
/Sometimes he thinks that other Amy, with her years alone and her hard edges, would be able to understand him and his plastic memories better than his Amy can./ - Oh, now I'm just floored.
And the final bit with Rory and River made me almost teary.
And the ending!
Oh, Rory... The whole fic is just so brilliant and clever!

Oh, and since I'm here I have to say I enjoyed very much you Spuffy "Prism" too, even if I didn't take time to comment when I first read it, shame on me! ;)