Many PS2 discs contain large amounts of empty "padding" or "junk" data used to fill the outer edges of the physical disc for faster reading. Removing this alone can often drop a 4GB ISO down to under 1GB without losing any game content.
Many PS2 games contained "dummy" files pushed to the outer edge of the disc for faster loading. These are deleted. ps2 iso highly compressed under 100mb patched
The open-world map is preserved, though the "Blacklist" videos are often lowered in quality to meet the storage goal. ⚙️ How to Play Patched ISOs Many PS2 discs contain large amounts of empty
For a technical look at how the PlayStation 2 hardware itself handled data to save space, the most relevant paper/technical analysis is . ps2 iso highly compressed under 100mb patched