Minus the poorly done ending, this was really great. Sooooo smooth, though it did feel a little repetitive at 1:25 when you introduced the new pattern, largely due to the lack of background (the lazy way around this problem is just reducing the number of repeats). On the ending, the fact that you only let the remaining noises die down for half a second seemed a bit... abrupt. It feels like it could loop really well, but you haven't done that either. If you fixed the issue with the finish, it'd be 5/5.
Just my opinion.