A (Compressed ISO) is an ISO file that has been compressed to save space. This is what users mean when they search for "Highly Compressed."
The original game file is roughly 600MB to 700MB. A highly compressed version (often in .CSO or .RAR format) can bring that down to under 400MB without losing game quality, making it ideal for devices with limited storage.
When we talk about a version of a PSP ISO, we are not simply talking about a standard ZIP or RAR file. Web-based compressors and specialized tools (like UMDGen, CSO compression, or advanced repackers) use two methods:
