The opening was brilliant! Very atmospheric!
The strings were very well used along with the brass! Simply sublime use of the brass. The flute could have been a little too bright in some places... the color wasn't very fitting around 1:20. The harmonies were a little drab until 2:20, to be honest, but the major sevenths and diminished chords gave it the spark of interest it needed. The section around 2:50 was very well placed, but I think that the strings playing that high would produce enough volume to overpower the winds at that register.
At around 4:20, I guess I could have used some change... the low register stuff was getting a bit tiring. Some oboe and trumpet exchanges in that section would give it the perfect punch, imo. However, I did finally begin to feel the march feel at this point and the orchestration was brilliant. Also, the repetitions began to overwhelm me as I think you intended.
At around 6:50 my ears were getting tired from the homophony too. If you are going to do this, you might as well throw in a new theme or a different variation of the theme to catch SOME interest
. Maybe some chromaticism would help too. The harmony at 7:45 wasn't very convincing.
From there until 9:34, there wasn't anything that really stood out, good or bad.
At 9:34, the increased rhythmic interest helped. 10:50 was exactly the contrast that I needed to keep me listening. To be honest, that whole section from 7:45 to 9:34 didn't catch my interest at all, which is something almost essential in pieces of this length.
You did manage to beat the theme into my head though
, so yay for that!
So, I gave my thoughts on it overall, and I really really think that it could benefit from more counterpoint or more harmonic changes. Look at Beethoven's Funeral March from Eroica, for example... it's so wry and sarcastic when it comes to death and the violins, winds, and brass all have long conversations about the topic. When worst comes to worst, the climax is given by extremely powerful string writing.
Good work, nonetheless!