You need to place your own game files onto the SD card before running this N64 Emulator.
MegaN64 is a modified version of the Open Source project Mupen64+, which is licensed by GNU GPL v3. Modifications include performance enhancements for specific Phone Models such as the Nexus 4 and the Galaxy S4 and small UI improvements.
If you like MegaN64, please donate to the developers of Mupen64+ by purchasing the app here: https://play.google.com/store/apps/details?id=paulscode.android.mupen64plus
For the license, visit http://www.gnu.org/licenses/gpl-3.0.html