I took a quick look at the plugin and it looks like it depends on the diff
command line utility. I dont think it comes installed with Microsoft Windows, but if you manually installed it, id open a new terminal and try running the diff utility manually to see if its on the executable path.
But if you want to try installing it, I think it comes with Git bash for windows.
I hope this helps, have fun with Neovim!
Dolphin + mpv for me so I can see the album covers and metadata and see whats available, if I have a specific song in mind, then ill just use the terminal and mpv.