Fantastic.
I wasn't sure about the waves at first, but I came to like their thickness.
The stringed instrument sounds quite real, is it? My guess is a good synth, given what you have to work with.
You had a great sense of timing throughout this piece, I liked the pauses.
It could be considered a bit simple, in terms of the number of sounds used, but I found it well composed despite that. Also, the quality of each sound is well balanced with the others.
The shakers added well to the atmosphere, and the base provided a nice warm undertone.
The horse galloping at the end didn't sound out of place, so props on that.
The pad (pretty sure it's a pad) reminded me of the voices of the four masked giants from Majora's Mask.
All in all, I think this piece was well thought out and well composed. Good job!