If you downloaded a "RIP" version, the music is gone to save space. To get the full experience, look for CHD versions instead—they are larger than RIPs but smaller than ISOs, and they include all audio.
PS1 games originally came on CDs, which held roughly 650MB to 700MB of data. A standard ROM file (ISO or BIN) is an exact copy of that disc. If you have a library of 50 games, you are looking at 30GB+ of storage space.
A haven for a strange breed of digital archaeologists—people who took original PlayStation games and crushed them down to absurdly small sizes. Thunder Force 2077 had been compressed to just 19 MB. No videos, no music, no textures. Just the core gameplay loop, running on a skeleton engine. It was a ghost of a game.
No matter how compressed the game is, you still need the PS1 BIOS (usually scph1001.bin ) for the emulator to "boot" the game.
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