GameEx Arcade Edition is a derivative version of GameEx that is optimized for arcade controls, arcade machines, and HTPC systems where only gaming is wanted. It was originally designed for arcade game setups only but also supports any emulation system.
Android:
Install and open Downloader (by AFTVnews) from the Play store.
Enter 246452 for GameEx or 629105 for GameEx Arcade Edition. The APK file will download direct from here.
The first time will issue a security warning. Follow the prompts to allow unknown apps then repeat the download.
If you receive a privacy warning, select install anyway.