The PSP simply cannot run a PS3 game, and PPSSPP (a PSP emulator) cannot play PS3 titles.
If you are looking for an authentic Kratos experience on the PPSSPP emulator , there are two highly acclaimed official PSP titles that run flawlessly: Download God Of War Ascension Ppsspp Iso -
Any site or video claiming to offer a "God of War Ascension PPSSPP ISO" is likely providing a modded version of a different game (usually Ghost of Sparta ) or misleading files. How to Actually Play God of War: Ascension The PSP simply cannot run a PS3 game,