That's a quite good song.
At first I noticed the lack of "special effects" you usually put in your pieces, but it seems it's because you recorded it live, isn't it?
In my opinion, some parts of the song are too silenced; makes it sounds like just a "rain", and only become a real "tempest" at 01:30~2:00; maybe it would be nice if you added more notes along the song to symbolize the numerous drops hitting the ground?
By the way, very nice effect with the double notes. This song has a very good harmony.