"Highly compressed" doesn't just mean a smaller file; it involves specific technical methods to reduce the data:
: Using modern compression tools like 7-Zip or converting ISOs to CHD or GZ formats can reduce file sizes by up to 40-50% while remaining playable on emulators like PCSX2 or AetherSX2 . How to Compress Your Own PS2 Games If you have a game you want to shrink, follow these steps: Highly Compressed Ps2 Games Under 100mb Free
: Compressing or removing high-quality FMV (Full Motion Video) and high-bitrate music can drastically cut the size. "Highly compressed" doesn't just mean a smaller file;