The GBC.emu app is an advanced open-source GB & GBC emulator based on Gambatte. It is designed to run games and emulators in the background, and allows you to control your games from the lock screen. You can even set it to pause your games when you leave the app or when the screen is locked.

The main focus of the app is to provide a very high level of audio and video latency. This allows you to play your games and use the app as a game controller for a variety of devices, from the original Xperia Play to modern devices like the Nvidia Shield and Pixel phones.

To achieve this, the app uses a customized version of the Android OS to provide a low-latency, high-quality audio and video service.