“You downloaded the wrong one.”
This is not a 1:1 port of the PlayStation 2 or GameCube version. It is a specific port known as (originally released on iOS/mobile and ported to PSP homebrew). “You downloaded the wrong one
Searching for "highly compressed" ISOs is one of the most common ways to encounter online security threats. you need the PPSSPP emulator.
If you find a download link with those specific keywords, it is usually one of the following: A Modded Version of " Resident Evil: Mobile Edition “You downloaded the wrong one
, but these are frequently the PS2 version (requiring a PS2 emulator) rather than a PSP-native file. How to Play RE4 on Mobile Devices
Before you play, you need the PPSSPP emulator.