Its alright. I can listen comfortably until around 1:26. I think the change at 1:39 should've happened a couple measures/loops earlier than it did. Ehh, and then after that it doesn't really change much. Its a decent kind of track, but even minimalist songs should have more build-ups than this. You just do it subtly, and layer things. Maybe you could add some type of eerie choir or something. I'm not trying to bash your track, just give you some advice. The intro sounded cool.