What's with the 3 minutes of silence at the end?

I'd suggest cutting that off and uploading an updated file...

Now, then, on to my review... this is a well-constructed composition. Some thoughts from while I was listening:
-Who the heck is going to be able to play that piano part? That just seems insane to me!..
-The piano is too quiet compared to the rest of the band (by the way, what is the instrumentation?)
-Nice playing with rhythms there - piano seemingly in one meter, the rest on another
-1:30 is pretty inventive. Great use of marimba
-As 1:40 and onward rolls around, it seems to me that those high instruments playing the three repeated notes should be playing different notes already (but with the same rhythm). The underlying harmony has changed, and it's beginning to feel weird.
-1:52, ok, back to theme 1 for a bit...
-2:17, ah, now this is a more interesting theme 2. Nice use of xylophone & marimba to create interesting texture. They go really well with the low brass
-back to theme 1 & a conclusion. Ok, that works. Pretty good ending.

I wouldn't say it sounds circusy, but it is pretty interesting. I especially loved the textures you had in places. It would, of course, sound a lot better if the sounds weren't so obviously MIDI-sounding. There are a few people on Newgrounds who judge based on the underlying composition (I try to, because I have the same problem myself - I don't really know how to work with electronic sound), but most people will base their judgement heavily on how rich and deep-sounding your sound file is. Hence why some really boring and derivative New-Agey stuff that nevertheless has a nice sound gets high scores. And I can't really give much advice either; as I said, I have the same problem (I use Finale 2007, which does have some good audio tools in addition to the scorewriting part of the program, but I have no idea how to fully use them. So my pieces also don't sound as good as they could. And there are a number that I haven't uploaded yet because I'm not happy with how Finale's making them sound).