All I could find on this was the publisher's info "Aeria". They have moved on to other things and seem to have about 6 games of various types on their main page. Unfortunately "Domo" isn't one of them. The video game midi/sheetmusic sites I use don't even know that this game existed - probably because it wasn't a console. All the "Domo" wiki says is when the various servers were shut down for various countries.
I even tried Google to find song lists or credits to no avail. Google did let me into a locked forum somewhere off the Aeria forums page, but the thread had no data on the music.
This may have to be done "by ear", which lets me out of the construction. I've only made one song by ear, and it was a short, simple one. If there was anything else to go on I could assist - even scraps of sheet music or guitar tabs would help.
When I listened I identified voices for violin, koto, flute, drums, woodblock, cymbols, and either bass guitar or viola.
Best of luck with this one. It will be a true challenge.