After listening to this piece on loop for awhile, I realized why this song brought on so much nostalgia! It reminds me of the Sarge's Heroes theme for N64 and PS1 (and the only-in-your-dreams-cast).
1) I would suggest that you extend the beginning and add a crescendo to the part where at 0:25 where the bells come in and the rest of the band stops so that there's more build up to the stark contrast of a full orchestra at fortissimo and silence with only the reverberations of the bell.
2) The piece feels a little empty in places. In band our teacher would always stress the balance of parts to be akin to a pyramid. Tubas, lower brass, and low woodwinds at the base, saxophones and french horns in the middle, and flute, piccolo, clarinet, and oboe at the top. For example, at 0:18 those trombones come out of nowhere, but they are either piano in the beginning or nonexistent. If the piece went from piano to forte at that part it might sound better, but as it stands now, it sounds like you're cutting out a section and putting it in later because the trumpets and percussion are too loud to make any musical difference at that point. A good example in your piece is 0:23 to 0:45 where the sound is nice and rounded, no one part is sticking out and the harmony of it makes it actually sound louder than what it might actually be.
3) Depending on whether you want this piece to loop or to have definite beginnings and ends is up to you, but I believe that a piece such as this should have a defined structure to it. Something to make the audience feel something. Whether it's joy, sorrow, fear, excitement, or curiosity, the goal of any piece of music is to invoke an emotional response from the listener and connect to them in some way. What does war mean to you? What SHOULD war mean? As I listen to this, I'm imagining my grandfather marching on the Germans with the 442nd at his side. Maybe instead of the glory and victory of the allies, you could depict the hubris of the axis, slowly winding down and accepting defeat at the hand of an enemy they thought inferior?
Anyway, that's just my two cents on your piece. Remember, this is YOUR music and you can do whatever YOU want with it. If you feel pressured to conform to my dumb little thoughts, only do it if YOU truly think it would make your music and you better. Just keep making music, the rest will come naturally. (Besides, this is better than anything I can make.)
Keep up the good work