Even with a verified ISO, you may hit snags. Here are fixes for the top 5 problems:

If you haven't already, download and install the PPSSPP emulator on your device. It's available for free on the official PPSSPP website.

(which features the 60+ character roster and the "Create-A-Fighter" mode), you should use emulators designed for its original platforms: PlayStation 2 Nintendo Wii on PPSSPP or finding a guide for the PS2 version Mortal Kombat Armageddon [Premium Edition] (2006) PS2 Game

Fire up PPSSPP, select your fighter, and remember the golden rule of Mortal Kombat: There is no knowledge that is not power.