Kind of a strange request I guess. Mostly due to nostalgia.

Is there anyway to enable the midi audio tracks instead of the CD audio?
There doesn't seem to be a way to set it up in the setup executable.

In the SW.CFG file there is a music device variable that is set to:
MusicDevice = 13

Can I set this to a different number to get the midi audio tracks to play?

Thanks.

Strange, as the shareware version most certainly did.

Not really. I downloaded and played shareware version from 3drealms site earlier and it didn't had midi, only the same music like in full GOG version.

I just checked my Shadow Warrior CD. Skimming SW.grp, it didn't look like there were any midi files. Checking goodies/midi, there're FIVE midi files along with the following text file:

Don't know where you got that information but MIDI music was only introduced for the shareware version because there was no way how they could have implemented CD audio into a demo. It seems that only the five songs heard in the shareware episode even were officially converted to MIDI (as Smoke39's post suggests). I think you may have confused Shadow Warrior with Blood, where indeed MIDI music is available as a legitimate alternative to CD audio in the full version.