Phantom Dust is *out* for Windows on the Windows Store right now! https://awoo.space/media/uO6qxps7dEdeJh56kak
If yr having trouble finding Phantom Dust on the web Microsoft store, here's the link: https://www.microsoft.com/en-us/store/p/phantom-dust/9pcdnbhr11mr
And yes, it's free. There are optional microtransactions for the multiplayer mode, but nothing free-to-play interferes with the single-player mode.