At around :20 or so you do a quick "twiddle" (I'm unsure of the term off the top of my head.) and it's good, but it kind of clashes with the slow violin in the background. Also your loop point has about a a half second hitch, more than likely just an editing issue that's easily fixed.
However on the whole I like this song, maybe a tad too varied to be a loop, but once again, if you fix that little hiccup at the end it would be about twice as good as it is now.
Overall 4/5, only some minor complaints that are easily remedied.