Enter —the legendary PlayStation Portable emulator for Android.
If you bought RE4 on PSN for PSP/Vita, you can technically extract the EBOOT.PBP and convert it to ISO using PC tools (not covered in depth here). Resident Evil 4 Download Android Ppsspp
Download the Dolphin Emulator or AetherSX2 from the Play Store/Official sites. Resident Evil 4 Download Android Ppsspp
Be cautious when searching for "PPSSPP" downloads for games that weren't on PSP, as these sites often bundle malware with their downloads. Resident Evil 4 Download Android Ppsspp