Since these are fan-made modifications, they are not available on official storefronts like the Google Play Store.
To get one of these heavily modded GTA experiences working flawlessly on your Android device, you need three essential tools from the Google Play Store: the PPSSPP Emulator, a file extractor like ZArchiver, and your downloaded 7z archive. Step 1: Extract the 7z Archive Open and navigate to your Download folder. Locate your downloaded GTA V PPSSPP.7z file.
Most legitimate, working files under this name are fan-made modifications of actual PSP games. Developers take GTA: Liberty City Stories or GTA: Vice City Stories —which run natively on the PPSSPP emulator—and alter the game assets.