I like the general idea, but two things:
- I think the piano and cello clash.. their sounds get lost in eachother as they seem to be on the same octave (maybe push the piano one octave higher to give it more separation? or vary the volume the notes are played?)
- The cello drops out (good) and the piano moves onto a new phrase.. but for me it just sounds a bit too monotonous.. as if it has more notes than it really needs to have. Just sounds a bit robotic..
Maybe adding in some volume dynamics.. start the line off loud then calm it down, or slowly build it up or something... ?