Does need work, but a really nice start
You said it's a demo, so I feel I have the right to make constructive criticisms.
The first atmospheric/strings synth that comes in ought to be blended as it changes between notes; otherwise it sounds too artificial, unless that's exactly what you were going for in writing this. The same goes for that horn/trumpet synth.
I like the other background sounds a lot. It might sound kind of cool if the treble-bass balance was shifted a little towards more bass in some of those low drifting sounds at the beginning of each musical phrase, but that's just my personal opinion, and my headphones suck anyway.
Keep up the good work.