There is because the game was never released for the PlayStation Portable (PSP) . Any website claiming to offer a "verified" ISO for this platform is likely providing a fake file, malware, or a fan-made "homebrew" project that is not the actual game. Official Platform Availability
Since the actual Castle Crashers Remastered exists on the (a PSP successor), many search engines confuse the two. A Vita game is not a PSP ISO. They are incompatible. You cannot run a .vpk (Vita file) on a PSP-1000, 2000, 3000, or Go. i castle crashers psp iso verified
Any file claiming to be a "verified PSP ISO" of Castle Crashers is likely a fan-made project, a "skin" of another game, or potentially harmful malware. If you want to experience the game legally and safely, here are your best options: Official Platforms for Castle Crashers Modern Consoles : You can play Castle Crashers Remastered Nintendo Switch PlayStation 4 no official Castle Crashers PSP ISO There is