RetroArch

RetroArch is the official Android release of the libretro project's all-in-one frontend. Instead of being a single emulator, it loads "cores": small plug-ins that each emulate a console, a home computer or an arcade board, or run a game engine. You download the cores you want from inside the app and play everything through one consistent interface.

Because every core shares the same menus and settings, features such as controller mapping, save states, rewind, shaders, netplay and achievements work the same way across systems. Run-ahead can cut input lag below that of the original hardware, and the menu is designed to work with a gamepad, touch screen or TV remote.

RetroArch comes with no games or BIOS files. Use your own legally obtained game backups, homebrew, or the freely licensed content that some cores support. Some cores need a reasonably powerful device.

Source: official APK from buildbot.libretro.com (linked from retroarch.com). Developer: Libretro. Licence: GPL-3.0.