Use ZArchiver to extract the zip file. You should see an .iso file and sometimes a PSP folder containing "Save Data" or "Textures".
Despite being fan-made, these projects aim to replicate the intense atmosphere of the original 2005 masterpiece : Resident Evil 4 Ppsspp Zip File Download
Mapping the complex GameCube/PS2 controls to the PSP's limited button layout or mobile touchscreens. How to Install Resident Evil 4 on PPSSPP Use ZArchiver to extract the zip file
While was never officially released for the PlayStation Portable (PSP), the power of the PPSSPP emulator and the dedication of the modding community have made it possible to experience Leon S. Kennedy's nightmare on mobile devices. How to Install Resident Evil 4 on PPSSPP
Watch these gameplay showcases to see how the fan-made Resident Evil 4 performs on mobile hardware through the PPSSPP emulator:
Many "Highly Compressed" zip files (often under 120MB) include HD texture packs to improve visual clarity on high-resolution mobile screens.