Square Enix hasn't officially uploaded the Parasite Eve soundtrack to popular music streaming platforms like they've done for Final Fantasy, Mana, and SaGa. Rather, here's a shortcut to YouTube for soundtracks uploaded by fans.
Here are some album covers for the soundtrack. The first one is the official cover. The second is a vector tracing of the logo.
The best place to listen to Parasite Eve fan music is at OverClock ReMix. They offer hundreds of songs! They have also uploaded their music to YouTube.
Just like with Parasite Eve 1, Parasite Eve 2's soundtrack hasn't been officially uploaded anywhere. So here's a shortcut to YouTube for soundtracks uploaded by fans.
The fan base has gone a long way with emulation. In the early 2000s, they came up with 'extracted game music' (a.k.a. chiptunes). They extracted the programming of the music from every classic video game and built digital soundtracks with them. With special music players, you can play these music files as if they were MP3s. And they're far better quality than MP3 because it's the actual programming of the song that you're listening to! In this realm, PlayStation 1 music is under the 'PSF' file format. Music players that support PSF can be found on any device: Windows, Android, iOS, Mac, and Linux.
My favorite feature about this music is how small it is. Parasite Eve's PSF soundtrack is around 5 MB while an MP3 soundtrack is around 300 MB! So you could quite literally have hundreds of classic gaming soundtracks on your iPhone or Android phone, and barely make a dent in your phone's storage.
If you want to learn more, read my tutorial for Extracted Game Music. My tutorial also provides links where you can download PSF music; their libraries will have Parasite Eve's soundtrack (and the sequel). Extracted game music can be converted to MP3, too. My tutorial provides directions on that process.
MIDI music is a relic from the early days of the Internet when it was the only music we could download with our slow dial-up connections. It's fan music because MIDI files are made by people playing the songs on electric keyboards. The #1 website for video game MIDI music still exists today: VGMusic.com. There you can download Parasite Eve's entire soundtrack in MIDI format.