Very nice work with the voice recording. You went the extra mile and it really adds great atmosphere! I like the little motif played by that kalimba (?) in Nightfall, might make a catchy theme in its own track.
You know that (usually hilarious) game where you cut a piece of paper in half and then two people have to draw one half each of the same animal? Making a soundtrack as a team is very similar, and your pieces fit really well together!