Linux version is a joke. RPGM uses very outdated version of nw.js that won't work in any modern distro. Moreover, nw.js is a bugged piece of shit itself. Font problems, codec problems ... whatever but not a stable work.
A lot of versions of nw.js don't suit Treasure of Nadia. However I've got the game to run brilliantly on every Linux system I've come across as follows.
1. Download the 0.42.6 version of nw.js from here:
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Click the "Previous releases" link and navigate to the 0.42.6 version that suits your system. Usually this will be the 64-bit Linux version below:
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2.
Download the 0.42.6 version of the shared object libffmpeg.so from here:
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The correct one for the 64-bit Linux version mentioned above is:
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3:
Extract the folder in file the nwjs-v0.42.6-linux-x64.tar.gz archive somewhere writable and rename the folder if you care to. I'm going to keep calling it the nwjs folder for reference in future.
4:
Extract the libffmpeg.so from the 0.42.6-linux-x64.zip file into the lib folder inside the nwjs folder to replace the original, which hasn't been complied to play mp4 video.
5:
Copy the www folder and package.json file from the Treasure of Nadia folder to the nwjs folder and you're pretty much done. (You need the package.json in order to read and write from/to wherever your previous saves are located. ) To test the game open a terminal, navigate to the nwjs folder and run the game by typing ./nw at the prompt and hitting enter. When I did this the game started up but it is possible on your system that the nw file might not have been set as an executable. If this happens type sudo chmod +x nw, enter your superuser password and hit enter or set the executable bit in the file using your GUI.
Most Linux now comes with a polished GUI and so you should be able to add a launcher to the nw executable to your Desktop and/or some menu to execute the game with a click of the mouse or tap of the touchpad.
Always works for me and I hope it works for you.