Great, but could be better!
This piece is an amazing success. The percussion section was great, and everything seemed well arranged. There are very few things that I dislike about this piece. However, I do think the brass section sounds a bit strange in a piece that is aiming for a tribal feel. It goes fine with the percussion, but brass instruments just don't, in this case, fit that "tribal" tone. They sound more reminiscent of the great mountains of Western Europe than the plains and valleys of Aztec-dominated Mexico.
Additionally, the piece seems to drag considerably in the second half (specifically after the 2:00), and everything begins to sound a bit flat and anti-climactic.
Overall, I really liked the piece. It's great as it is, but if you're willing to work on it some more, I'm sure it will be even better!
Good work and good luck!