It's been so long since I've reviewed a piece of music, but after you left the review on my track it's only fair for me to return the favour!
So I've given this a good few listens and what struck me the most was the unsettling atmosphere. Nowadays I find that a lot of horror soundtracks feel like cop-outs. They throw together whatever shrill and unsettling sounds they can find into a hodge-podge of atonal ambience that may seem fitting in whatever background they play in, but as standalone tracks they have no musical meaning. As such, it's nothing short of refreshing to hear a horror piece with great ambience that actually has melodic substance in it!
I loved your use of background sound effects. The laughs from the child and the wispy, brooding swells of the chasing shadow really do sell the piece's chilling atmosphere, and they're quiet enough to be considered subtle while still loud enough to be audible. 0:42 and similar parts have a instantly likeable vibe that's incredibly reminiscent of old horror soundtracks.
Actually, in general I'm a fan of your chord choices. You make fairly occasional use of stereotypically "happier" chords like major and sus2, but throw in enough minor/augmented chords and notes to break up the generally happy connotation of the major chords, which is a great way to sort of melodically tell the story of a child playfully running around a mansion, unaware of the sinister force tailing her.
My main gripe with the track is that it's simply unable to hold interest for the full seven minutes. You follow the same pattern of broken chords for pretty much the entire track, and repeat the same chord progression multiple times on a macro and micro level. By the first 2 minutes, we've heard pretty much all the track has to offer, beyond subtle ambience changes and some rather neat vintage-sounding EQ towards the end.
Unlike the below reviewers, I like the piano sound, but the cinematic composer in me is dying for some more dynamics on it. The slight ritardando at 1:14 and the little break at 2:05 (and the similar one later on) felt like a breath of fresh air. More of that stuff!
Of course, if you go overboard on dynamics and the song starts to lose its proficiency as a background piece, but I personally believe that a lot can be done to the dynamics and subtlety of a piece while still retaining its context as something that sits in the background. Adding more dynamics will also automatically solve my aforementioned criticism of the song struggling to retain interest for a full seven minutes.
Overall, if you were setting out to tell a chilling story, then you certainly achieved that. This was a fun listen with a refreshing amount of melodic substance and good, non-cheesy usage of sound effects and background ambience. Nice work!