Mortal Kombat X was never officially released for the PlayStation Portable (PSP) or the PPSSPP emulator. While you may find links for a "highly compressed" ISO file, these are typically fan-made mods of older titles, like Mortal Kombat: Unchained, designed to look and play like the 2015 console hit. Understanding the Mortal Kombat X PPSSPP Mod

Disclaimer

Offline Play: No internet connection is required once the file is set up. How to Download and Install MKX PPSSPP ISO

Download Considerations:

Controls: Touchscreen controls are difficult for complex combos.

Advantages: