Great stuff. Love the composition and the atmosphere, however, the arrangement and mastering could take some more work. As for the arrangement my main concern is the percussion. I think the way you used the snares wasn't too good, I think they should have a more complex rhythm and you could add some other instruments as well, add some accents, add a few more powerful strikes. Also in the and the compression hurts the overall sound a little. Aside from that amazing work. :)
Please contact me if you would like to use this in a project. We can discuss the details.