Lot of questions from people--I'll try to answer some of them.
This is an incomplete of songs (as many of you guessed). I've downloaded 47 tracks out of a list of approximately 100. Most of the rest are short cut-scene tracks less than 30 seconds in length.
Yes, there is an Orchestra Piece #1. If you can find this at all, it is a MUST to download.
Yes, there are tracks for every boss battle. They are amazing.
thehylia.com used to have a FlashPlayer list of the complete soundtrack, but upon finding out it was still possible to hack mp3 files from their site, they have since removed it from their site.
Search elsewhere for more files. Happy hunting.