While standard PSP games range from 200MB to 800MB, compression tools can significantly reduce these footprints. : The standard uncompressed disc image format. .CSO (Compressed ISO) : The native PSP compressed format. Tools like YACC (Yet Another Cso Compressor)
"The game could not be started (80020148)." Fix: Your PSP lacks Custom Firmware. You cannot run ISOs or CSOs on a stock PSP. Install PRO-C or LME CFW. metal slug psp iso highly compressed