Play the game's SND0.AT3 when a game is selected in the menu and on the "game screen".

Just like when selecting the game on the PSP :)  Note that mouse selection won't do it, use the arrow keys or dpad on your joystick. Or just click and hold to get the game screen and hear the music. Not all games have this music.

Would be cool to also play the little video too if available but that's a later project.
I don't think they can change in practice. We could probably initialize it before the first frame by querying somehow.