It works under DOS. I did some work but not enough for it to function flawlessly. There are two problems with it, both concerning MIDI playback: the presets are loaded incorrectly by DOS utility, and the Miles driver won't play drum part correctly (even if presets are correctly loaded). But the first can be avoided by running Windows 3.1 with Multisound drivers which load preset correctly, then exiting Windows. To fight off second one I modified Miles driver to remap GM drums to Proteus ones on-the-fly. The results are worse than in Multisound Windows drivers but acceptable anyway. My version of driver is here.
For digital sound playback, there's DIGPAK driver. Despite only few games support Multisound out of the box, you nevertheless can add the DIGPAK driver to any game using DIGPAK and off you go. For example, I managed to run Terminal Velocity on Multisound.
Hardware comparisons and game system requirements: https://technical.city