The problem for many with Alone in the Dark 1 is that it doesn't include the MIDI music of the original floppy release, which many people prefer. But the CD music is not more compressed then in the original CD release as far as I can tell.
Ok, let's put this to rest.
1.- GOG's version is the CD version which has uncompressed redbook audio music. It has the advantage of voice over and a better soundtrack, just that a lot of people prefer the old one because of nostalgia; it's not technically superior, at least with this game.
2.- Alone in the Dark has never had MIDI. Ever. Nope. Sorry. It always used Frequency Modulation through the OPL2 chip found in Soundblaster cards. For it to have MIDI you would needed a hardware sound module like the Roland MT-32 or Sound Canvas SC-55 to play back music.