This project looks fantastic, and it's something I've often dreamed of seeing or even making myself since I first played the games back in middle school. You guys have done an outstanding job meeting the high artistic standards set by DOTT.
As far as music, since the original PC version didn't have much, might I recommend basing your score on the NES version, which, for all of its problems, had quite a bit of very nice music?
This YouTube account has a lot of it up for listening:
http://www.youtube.com/watch?v=ZCafbkQ-RT8
And some MIDIs are here, which may be useful for you or whoever ends up doing the music, as you can fiddle with them or use the notes as the basis for something more complex:
http://www.vgmusic.com/music/console/nintendo/nes/index-gr.html
As far as music, since the original PC version didn't have much, might I recommend basing your score on the NES version, which, for all of its problems, had quite a bit of very nice music?
This YouTube account has a lot of it up for listening:
http://www.youtube.com/watch?v=ZCafbkQ-RT8
And some MIDIs are here, which may be useful for you or whoever ends up doing the music, as you can fiddle with them or use the notes as the basis for something more complex:
http://www.vgmusic.com/music/console/nintendo/nes/index-gr.html