Love the overall aesthetic and tone of this! The sprites and sounds go well together, harmonic minor is a nice choice of scale for the theme (instead of defaulting to pentatonic which would definitely give this a different tone), and the background noise is a nice touch. 

The main thing I would want to see out of this is more refined pitch mapping. It seems to just be based on character position now (if that's wrong, I wonder if you can make the actual mapping more apparent), but with the theming, I expected it to be based on ghost positions relative to the player, especially with the red ghosts. I imagine that some interesting sound patterns could emerge as you push the ghosts around. Side note: the current position to pitch mapping feels odd as it wraps before the screen edges. I actually like how this makes the mapping less "obvious" but those wrapping thresholds sound quite jarring.