VirtuaNES emulator (bottom screen) is a mod of bubble2k16's program (v0.94) created to be played only at bottom screen on your old 3DS and old 2DS. It's not as accurate as FCEUX or Nestopia, but it runs at full 60 FPS for almost all games, and supports tonnes of mappers: MMC1,3,5,6; VRC1,2,3,4,6,7; and tonnes of other mappers. As a result, the library of games it supports are huge.
This 3DS version also fixes a few bugs from VirtuaNES's MMC5 mappers and even plays Rockman 4 Minus Infinity and Zelda Legend of Link hacks.
Virtuanes3DS_bottom.3dsx (to be launched from homebrew channel)
Virtuanes3DS_bottom.cia (to be installed in home menu) [ Coming soon... ]