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.
Download file.
In Finder right click the application and select New Terminal at Folder
Copy and Paste all this into Terminal and press enter.
cd ..
chmod -R +x Mac_GameEx_ArcadeEdition.app/Contents/MacOS
chmod -R +x Mac_GameEx.app/Contents/MacOS
xattr -dr com.apple.quarantine Mac_GameEx_ArcadeEdition.app
xattr -dr com.apple.quarantine Mac_GameEx.app
Then launch the application.