Citra MMJ is an unofficial fork of the Citra emulator that has Android-specific hacks in order to improve performance on smartphones in the pursuit of getting playable frame rates. From what could be gathered on a thread in r/EmulationOnAndroid, this emulator, which originated on the Chinese forum Weibo, was recently marred in controversy as its release was apparently breaking GPL since the source code wasn’t provided when the binaries (in an APK) were published.
However, things have cleared up now as the emulator’s source code was published on GitHub and an easily-accessible APK file is available for download (link below). According to its GitHub release page, the emulator requires you to have a 64-bit ARM (ARMv8/arm64) Android smartphone running Android 7.0 or above so if your Android phone is a bit old, you’re probably out of luck. Furthermore, your phone needs to have a beefy SoC (System-On-Chip) such as the SnapDragon 845/855 in order to get playable frame rates in any games. As a result, it could be said that 3DS emulation on Android is more or less limited to flagships such as the Samsung Galaxy S10 or the OnePlus 7 for now

According to various user reports on Reddit and elsewhere, these games are currently playable provided you have a beefy-enough phone:

  • Persona Q runs almost perfectly on a SnapDragon 855Fancy playing some New Super Mario Bros 2 on your Android phone? If you have an adequately powerful device, you can! ( )

  • Return to Samus works very well on a Snapdragon 845
  • Rune Factory 4 runs well
  • Pokémon Ultra Moon runs at 30 FPS (full speed) on a SnapDragon 855
  • Pokémon Omega Ruby is running at 30FPS in some places
  • , New Super Mario Bros 2 is running at 60FPS most of the time, Pokemon Y works pretty well and TLZ: Ocarina of Time 3D can maintain 25-30FPS most the time (runs at 30FPS normally)
  • works decently although there’s slow-down in battles
  • More tests can be found by checking the videos on MasterKillua’s channel
  • Please note that I was personally not able to verify any of these performance figures as I’m not in possession of a high-end Android device

Citra MMJ’s GitHub Release Page (download link):