Marat Fayzullin has ported his (commercial) MasterSystem, GameGear, SG-1000, SC-3000 and SF-7000 emulator MasterGear to the Android platform: MasterGear for Android
Quote:
* Audio quality significantly improved.
* Switched to the new, fully configurable virtual joystick.
* Optimized screen updates sync, for better framerates.
* Fixed cut-off landscape display on Nexus7.
* Added two more Freeze/Restore slots.
* File selector now memorizes the last selected position.
* Added option for keeping screen on at all times.
* Fixed support for Sixaxis gamepads.
* Fixed a bug in the Z80 CPDR instruction.
* Added support for opening files directly from file managers.