Hi, just to add to Tommi's comments, we actually have already a perfectly working technology to make Linux and MacOS desktop versions of the game (SDL2+OpenGL2+Nuklear), but that seems to port a bit poorly to mobile platforms. Ideally, we'd like to achieve the mobile audience, as a retro game like this is probably best suited for mobile platforms, but it may be that we have to do with whatever technology we manage to get working with GnollHack/NetHack.
The current graphical version is based on NetHackW (Windows GUI), but moving to SDL2 and OpenGL seems pretty straightforward, although it does require quite a lot of new coding to implement menus etc. in NetHack, all of which had already been done in NetHackW. But we'll investigate this further and hopefully we find a good all-around solution to cross-platform development.