Though Dragon Quest’s music would be reprinted and re-recorded on many different albums, the original recording and (to my knowledge) the very first Dragon Quest music in existence are on this 1986 album.
With a complete score of only 8 tracks (each track getting three songs to go with it), Dragon Quest I is very limited for creativity. The music isn’t anything profound or inspirational; but, it is pulled off very well as the first VGM orchestra endeavor in history.
A type of track found on this CD but not on later Dragon Quest Symphonic Suites are the “Synthesizer Version” tracks. They are high quality, but definitely not “On Electone” tracks. I would have to say that these tracks are my favorite (even though each track is very short), as I have heard the orchestra versions of these songs too many times. The Original Sound Medley, again, would be good, but the use of extremely annoying sound effects just ruins the track.
Since you will probably never find this print of the album, you should settle for a “Dragon Quest I & II Symphonic Suite”, which exist in many different reprints from SPE Visual Works, Sony Records, and probably others.