It sounds like you're looking for a version of Red Dead Redemption to run on PPSSPP (a PSP emulator for Android/PC).
: Be cautious of files claiming to be "highly compressed" (e.g., under 100MB). Standard PSP ISOs for games like GUN are typically 600MB to 1GB. Files that are too small often have "ripped" content, meaning all the music and cutscenes have been removed to save space. Community Perspectives red dead redemption ppsspp highly compressed
Many websites claim to offer "highly compressed" ISO files to attract downloads. These files are often password-protected, contain malware, or are simply a different Western-themed game—like Gun: Showdown —renamed to trick players. The Hardware Gap: The original Red Dead Redemption highly compressed It sounds like you're looking for
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