Mael,
You've done a commendable job developing and building your thematic material--harmoncally, rhythmically and melodically. If "commendable job" sounds like I'm "talking down" at you, remember that you're one up on me in writing symphonically

. Nonetheless, speaking as one who is not orchestrally illiterate (listening-wise), I want you to know that, for the most part, your writing here has direction and proceeds in a sensible manner. You have gone beyond an exercise in imitation (cf, our "musical imitation" thread/debate); some very exciting and unexpected moments make this piece your own.
Commendations:
- You added timp! Mostly very good; I have a couple of qualifications below.
- 6:10--great transition around here
- 6:40--very nice melody: stylistically-appropriate, yet with direction and life
- 7:30-50--this was new material that manifested well-developed/recombined themes and ideas; great work
- 8:02--innovative layering of the two fragments of the first theme from the brass at the beginning
-8:00-16--effective, momentum-sustaining modulations
Suggestions:
- 1:25; 4:30--timp use: in both places, the timp seemed to invade the texture instead of supporting it. This especially struck me at 4:30 (and surrounding areas): are the double hits really necessary or just distracting? and does the section with strikes on every beat become grating? You'll have to decide.
- 9:12ff--As I realize you know, the energy here is as low as it gets in the piece: you have 26 seconds or so of pure quarter notes in the strings at about quarter note = 60 (I believe). I'd weigh whether this section serves to create a false lull (calm before the storm idea) before the smashing finish, or whether it simply deflates the forward motion and bogs you down (I didn't listen enough to decide).
Again, bravo. You've steadily kept at this project and pushed yourself to generate and manipulate ideas; such discipline is admirable. I think this movement will become only more effective when pitted against some middle movements and a rousing finale...hint, hint.

I suspect it won't be long.
Be glad that you have a work with both structural quality and originality; that takes effort!
Brooks