It's not beyond the realms of fantasy to envisage a web version; this is the first time ever that I've exported anything at all from Godot, so it may work, it may not. Linux..? Much more unlikely; even if I could successfully export it, I have no means of testing such a version. I'll strike up Godot and see what Web exporting entails. Thanks for the comments and suggestion; to be continued...
Edit : I tried, but haven't (yet...) got it in a state to be uploaded here. More research needed; back later...
Second edit : I got it uploaded, and it works, but I will have to modify it, to enable a 'Quit' function, and maybe make it full screen. I'll do it again, but (hopefully...) better. It's all learning, though, so it's all Good. :-)
Third edit : OK, I've patched in a 'Q' for Quit function, and enlarged the screen resolution somewhat. Yippee..!