needs meat
This whole song feels like the frame work for a real song thats not really there.
Your main "melody" which you repeat over and over is largely stepwise, rhythmically even and uninteresting until about 3 :15.
It largely improves after that point, however it's still missing somethings.
As of right now, the song feels largely ambient, without a very solid direction.
It feels like it's building towards something that never really comes.
The reason for this is the song never really changes much stylistically except for that change around three minutes so it feels like it's all "one part" of a song, rather than a whole song itself.
Try changing the instruments that the main melody is played on, make the melody a bit more complex or add a bit of effects to the mix.
There's also very little tension and resolution going on. most of the piece is simply fluttering around, and feels like a collection of sounds rather then a single piece.
Creating points of tension can help create direction.
Also, you add intensity to your background stuff that's going on, which is fine, but yo rarely give the melody the attention it deserves. if you are changing up the other parts and making them more intense/interesting, you end up listening to that stuff more rather than the main line. it takes away from the drive.
I have a couple more things i could touch on but i dont want to say TOOOO much.
To give a VERY brief summary of what i said:
The best part of the piece is from 3:15 until the fade out. You need to make the rest of the song like this, with drive and melody, rather then ambiguity and repetition.