This was disturbing at times, with Severus using Harry in place of his mother, but I think it worked very well with the man we know Snape to be; telling the story through his eyes really reinforced this. I love that Snape continued looking deep enough to see Harry in everything that was Lily and/or James.
Snape has a tendency to form obsessions, and that reflected nicely in the story as Snape stopped sleeping, eating, living, to spend time with his Pensieve and the Harry he slowly began to see.