NES.emu is an NES/Famicom (ファミリーコンピュータ) emulator written in C++ for Android, iOS, Linux, and WebOS. It uses the emulation backend from FCEUX and is built on top of the Imagine engine. The source is released under the GPLv3 license.
Accurate emulation and high compatibility rate, similar compatibility to FCEUX 2.1.4
Backup memory and save state support, auto-save and ten manual slots for save states. State files from FCEUX should work on NES.emu and vice-versa.
Supports ROM-based games in .nes and .unf formats, optionally in .zip files
Famicom Disk System emulation using .fds files (select your BIOS in the options first, either the original Nintendo one or Twin Famicom, should be 8K in size with either a .rom or .bin extension)
VS UniSystem support, push Start to insert coins
Zapper/Gun support, touch screen to fire, touch & hold outside of display area to simulate firing away from the TV
About Save Games:
For ROM-based games, a standard .sav file is created for those with battery backup
For Disk System games, an .fds.sav is created if a write is detected on the disk. This file is an exact copy of the original disk with the modified data so the original remains untouched and is used automatically upon loading the game afterwards.
Save states are named .fcs for the auto-save slot, and .fcX where X is the slot number for manual saves.
Performance Notes (as of version 1.3.11):
Android : 60fps with only minor hiccups on a 600Mhz Droid running Android 2.3.
iOS: 60fps on iPhone 4. 25-30fps on iPod Touch 2nd gen.
WebOS : 60fps on Palm Pre.
Input Ports: use Auto to guess what type of input device the game uses, or select a specific device
Multitap Support: enable to play 4-player games such as Bomberman, disable on all others