Installed Flatpak version on my Librem 5, but no touchscreen controls and I don’t see any way to enable.
I believe I had to go into the game, find the setup menu, find “controls” (or something of that nature), and then “enable touchscreen”. Something like that. It works well.
That was it, but it was not selectable when I was trying it earlier. Weird, but happy now. It’s a very playable game on this phone.