Hmm... the audio representation is ... okay. I feel like my impression is impacted by this, but here goes...
I liked the themes/motifs you used, they were each quite cool and it was very obvious which ones you were using at what time. I think you did an okay job with the developing, it was nothing special, but it was still good. What I'm trying to say, it although you did well with it, it didn't hold my attention well. Of course, again, I'm worried that I may think this because the mp3 was kind of icky, articulation was really not-crisp, if you know what I mean. I can see this as a backdrop to a silent moving picture (not necessarily a movie, per se, but something film-wise)... it even sounds rather reminiscent of old silent film scores, which I usually enjoy.
The ending I did not like... I feel that you need to find a better way to land in that final key, as it is, it sounds unresolved to me. Unresolved endings have their place and specific use, but this does not seem to me a very good example of such an employment.
I think you are doing well with this expansion of harmonic language... I'm not familiar with your style, so I can't comment personally, but I can say that this piece held together very well, even if there were some parts I would have changed in just the slightest and others that began to lose my attention, which brings me to my last words. Your work on developments seems fine enough, but work on making it more interesting, more varied, maybe try putting all the the main motives together in the same phrases to build depth and intensity, it also helps bring the individual motifs together and let them work with each other.
One final note: String instruments are capable of an almost endless variety of tone colours and styles of articulation, don't be afraid to employ them. If you know little of them, consult a local string expert, you can learn a lot and use that knowledge to aid you in your compositions, making them all the more enjoyable to hear and play.
Cheers.
