Just in case you are still curious, and I don't see any actual answers here. The download provided is all the code for the game engine and everything else that would be going on in the background of the game. Anything that could be copyrighted by Nintendo (things like character and object models, textures, music, and environments) need to come from a totally legit dump from an official Nintendo cartridge and definitely not any ol' .rom file you can download online
Got a mix of some metal, some rap, and some... EDM I guess? Have it all on a playlist on Spotify and I haven't really posted links in the comments before on Lemmy, but here's some of my favorites:
Cyberpsychosis by Rixat
GIRL HELL 1999 by Femtanyl
Willpower by Mohmega
Credits Song For My Death But I'm The Final Boss by Astron