This is a really interesting piece. I think my favorite part is how subtle you are, that's a very rare trait to find in Newgrounds Audio (no offense to anyone).
Reading your description its clear you really experimented to get a very interesting sound, and I think it pays off. I can definitely imagine this as a really cool bit in a video game, or interlude in an album, or in a strange movie soundtrack.
Regardless I think it hits an interesting mood and is well processed and written, it doesn't lack depth in the composition, what little their is. That's one of the toughest parts about writing such a minimal song like this, is trying to not make it sound lazy, like you were falling back on lack of composing skills. But it really doesn't here.
I love it, keep making music!