Download and install the free version (there is also a paid "Gold" version if you wish to support the developer, but performance is identical).

To address your search for a Resident Evil 4 PSP ISO for Android , it is important to clarify that Resident Evil 4

You can emulate the PlayStation 2 version of the game using AetherSX2. This version includes the "Separate Ways" campaign but may require a more powerful device than the GameCube version.

Can You Play Resident Evil 4 on Android via PSP ISO? Here’s the Truth