Oh whoops, that's my bad. I saw "Windows, Mac & Linux" on the build options in Unity, and assumed the build would contain support for all 3. Upon further review, it's just Windows. I'll correct that for now, and look into a Linux (and Mac and webgl) version soon.
I've now realized I don't have any way to playtest a Mac or Linux version of the game. If you'd like me to build a Linux version for you, I can go ahead and build it, but I can't guarantee that it'd even work. ¯\_(ツ)_/¯
