The highly compressed archive removes redundancy, but the emulator needs structured data. Temporary expansion is normal. Play directly from the compressed CSO/CHD – don’t extract those further.
Extreme compression sometimes involves "ripping" non-essential files like high-quality cutscenes or background music to save space. How to Play on PC & Mobile God Of War 1 Iso Highly Compressed
That said, here are common archive types you’ll encounter in community forums (Reddit’s r/Roms, CDRomance, Internet Archive): The highly compressed archive removes redundancy, but the