Actually, it's even worse.
The music uses all 16 channels indeed, but it also uses a pitch bend sensitivity of 12, while General MIDI uses 2 by default.
Selecting "General MIDI" in the install program, then running the game, correctly sets the appropriate RPN controllers to set the pitch bends to 12, but due to a bug in the TIM.EXE file, no music data ever gets sent after that. (How bad was their QA department anyway, that they didn't spot this obvious bug?)
Selecting "MT-32" in the install program, then running the game, sets the GM-emulating MT-32 patch bank, but then plays the music on channels other than 2-10, which you'll miss with an MT-32. You can use the SC-55 with this install program selection, but the pitch bends will be wrong, because the General MIDI init wasn't sent, since we selected MT-32....
Therefore, the ONLY correct way to hear the music as intended is to use a SC-55, first select "General MIDI" so that the proper RPN controllers get sent, exit the game, select "MT-32", then run the game with the SC-55 attached. Of course, you'll have to do this every time you want to play.
And that is why Dynamix is stupid.
That and their lack of "MT-32 plus Sound Blaster" option, even going so far as disabling MT-32/General MIDI completely in one game.