Thank you, I'm glad you enjoyed the game!
The OST is larger than the game because the OST includes the files in FLAC format, which is a lossless high res file format. The tracks were exported into OGG for the actual game, to cut down on file space, but the tracks in the OST should sound a little crisper.
I had suspected that at first, so was surprised when I found that the files were all .wavs. So, after reading your response I did some research though and apparantly it's possible for flacs and wavs to be the same. I made a copy of one and changed it to a .flac and it could still play just fine.
Well, I accidentally learned something! Thanks.