When trying to run the game on Linux it gives an error about missing a .pck file. I assume it was made using Godot ? If so usually there should be a .pck file alongside the executable.
Almost there :) The .pck file needs to be in a folder alongside the executable where currently it now just downloads the .pck file instead of just downloading the executable. I can confirm when the two are in the same folder the game launches on Linux so as long as you package them together as a download other customers should be good to go.