Whether you are a completionist or just someone who wants to fly through a virtual Metropolis without waiting for a slow download, using CSO compression is the Kryptonite-free way to go.
Websites offering "highly compressed PSP ISOs" are notorious for: superman returns psp iso highly compressed
Legitimate preservation efforts should rely on full, uncompressed disc images with checksums, hosted by recognized archives (e.g., Redump.org), not “highly compressed” scene releases. Whether you are a completionist or just someone
For example: $$x+5=10$$.
Before you hunt down the compressed ISO, you should know what you are getting into. The PSP version of Superman Returns is notably different from the Xbox 360/PS2 versions. uncompressed disc images with checksums