First of all, thank you for that awesome Doom-port.

The key remapping works fine, however, I have issues when switching back. I'm using my own key-remap which I saved in rx-51 file as 'my' and load it via setxkbmap my.
When returning from the game I've get the standard German layout (my native one 'de') but not the one I chose (namely 'my').
Is there a way to fix that?

About the music issue. Perhaps it's possible to use some from of fm-chip simulation. I know there some of those, but couldn't find any just now. Perhaps include music with the additional option to have one of those emulators running in the background.