Great piece here... sorry I don't have time to give a big review... I might delete this and replace it later with a full constructive-critique pile.
One thing I noticed was that you did a good job with having a strong melody, although it was rather cliche.
There isn't much of an ending here, consider some downward motion into a final calm closing... not sure if you have heard the opening to Wagner's Rhinegold, but imagine that motion turned around and greatly abbreviated so it fades away into nothingness. Alternately, some very broad hits of the same style as the cello marcato bits in the 1:20-1:40 area) over the orchestra in unison could work. Otherwise, you leave it at a cliff.
The tune seems rather cliche, but you did an amazing job mastering and preparing this (my only note is that some instruments seem to come from the wrong direction when compared to a traditional symphonic setup... brass on the left? violins on the right?... it's a minor detail, and may just be my crummy speakers), I think that makes up for whatever stylistic differences. One of my favorite things is when people actually try to make things sound real... and you did a good job here (I thought the concert "warmup" was a great idea).
Keep up the good work!
-Samulis