"Highly compressed" versions typically refer to files distributed in formats like to save bandwidth during download , though these must be extracted before they can be played. Downloading the Game
A compressed format designed for PSP that PPSSPP can read natively to save space. 7Z/RAR/ZIP: Highly compressed archives used for downloading; these must be extracted using tools like or WinRAR before the emulator can play them. Performance & Requirements Prince of Persia: Rival Swords Review - IGN
Change the audio backend in PPSSPP settings to (not “Fast”). Also, ensure your ISO is not a “rip” that removed audio files.
Yes. But Rival Swords works better on PPSSPP for upscaled graphics and save states.