Hey, I liked it a lot. I really like how you didn't try and stretch or go crazy, but just create something simple and solid. Excellent work.
Something to think about re: sound design, the piano sound is great, not sure if it's the actual piano or a sample library, but it has a great balance of note sound and wood. I like the idea of using a sound source from the film itself and combining it with the score. If we were actually standing in that house, the piano would sound different from each room and floor. It's tone would change, and the walls and nature of the space would shape the sound. As the actress moves from upstairs to downstairs, into the piano room, then to the kitchen and back, the piano sound would change as her perspective (and our perspective) changes. Since it mostly sounded like you used the close mic sample for the shots, the realism of the piano being played in the house was diminished, and it sounded like a part of the score, instead of something that the actor would react to as occurring in her space.
To make something seem farther away, you can roll of some high end from the eq, anywhere from 200hz to 5khz, and gradually bring it in until your'e in the same room, and the sound is in front of you. Also, experimenting with the kind of reverb used on the sound can change how we perceive the space. Convolution reverbs use actual reflections from different spaces, and can simulate rooms of different materials. Then, work with the mix of dry signal and wet signal to make the instrument sound closer or farther.
Sorry if you know all this already, and it was an artistic choice, just thought I would share. It sounds like you were thinking this way already, with the volume changes. Anyways, excellent job, enjoyed watching.