Sounds really good, I like especially the horns :)
Some points:
- Some of the instruments sound really dry. Try the same reverb for all instruments to glue them better to the same room.
- Your piece has potential to grow to a huge epic march towards the end. I would add more loud percussion and use the whole string section and actually the whole orchestra in the end. Maybe from the ascending line at 2:20 could be played by winds, strings and harp like John Williams would do and keep going with bigger orchestration. Sounds like the velocities on all instruments are just a bit too low. Now it sounds like the rhythm sections have to keep themselves down though they want to blast the piece out of hell. Of course I understand if this isn't your intention.
- Is the instrument at the beginning of the piece supposed to be a guitar or some keyboard instrument? It sounds fine but if the intention is to sound like a guitar it's a bit off. Needs more low middle in any case IMHO. And there's a small glitch at 0:29.
Just some small points to keep you busy ;)