This uses Cocos2dx, which is c++. Emscripten does not yet support Objective-C. Even if it did, someone would need to write an Objective-C runtime (probably not too hard, especially if you lean on Cappuccino for objj_msgsend). Once that hurdle is cleared, you'd need to source code for UIKit & whatever iOS frameworks you're using. What's more likely is a port of AppKit using Cappuccino components.