The index.php file is there to fool heroku into thinking your app is a dynamic app. Heroku doesn't allow static html to be hosted so we need something to get free hosting with heroku ...

Delta is easily one of the best GBA emulators for iOS devices ... such as support for online multiplayer, and you can even use RetroArch's shaders to emulate the look of a CRT TV.

For the GBA, there are many emulators available ... It offers many features like controller support, cheat codes, online and local multiplayer on supported games, speed hacks, and save states.