The original Ys Perfect Collection spans two CDs; in terms of musical styles and formats, the two discs are very different.
Disc 1 is the one most of us Ys nuts are really after. All 14 songs from Ys 1 are rearranged, but most importantly, all of these versions capture that intangible Falcom "sound", a certain spirited combination of shimmering guitars, crisp percussion and synths, and the occasional horn and flute thrown in. I was a bit disappointed to find that a few of the tracks were just repeated from the Music From Ys 1 CD, with some acoustic touches added to the mix. But rehashes aside, all the songs on this disc are terrific reworkings of the originals.
Disc 2 is more of a mixed bag. It starts with a really cheesy vocal track (I'm just not a big fan of vocals in game music, so as far as I know this might be quite good if you like this sort of thing). Track 2 has a "smooth jazz" feel, and then -BAM- track 3 is a hard rock fest. Following this are some new age selections, three good JDK Band tunes, and another vocal (featuring a beautiful, feminine voice- much better than the first).
The two discs are so different, it's a shame they weren't packaged separately. For me, disc 1 *is* the perfect selection of Ys 1, while disc 2 is more a novelty, albeit a listenable and entertaining one.