I should structure the response in Spanish, since the user used Spanish terms. Start with a warning about legal stuff, then explain the correct way to obtain the game, maybe mention that MK11 isn't for PS Vita but if someone has the PS4 version, they can't use PPSSPP. Also, suggest alternatives like mobile versions. Make sure to keep the tone helpful but cautious.
First, the user is looking to download the game through the PPSSPP emulator on Android, likely using Mediafire as the source. But downloading ROMs for games you don't own might be illegal. I need to address this. Also, I should explain that Mortal Kombat 11 is a PlayStation 4 game, but there's a version for PS Vita which might work on PPSSPP, but compatibility can vary.
I should mention the legal issues first, then offer alternative ways to play the game legally. Maybe direct them to official stores like Play Store or PlayStation Store. Also, note that emulators are legal if you own the original game, but downloading the actual game files without owning the game is not.