You have absolutely no clue apps/games are made do you? Do you know how hard it would be/the knowledge it would require of Xcode to make a simple game engine as simple as graal, than make AI bots for sparring along with similar scripts to graal. Not to mention you will also need a Mac (to code Xcode), a developer apple license (what is that $100?), server costs if it's multiplayer (that's another expensive thing, for a useless guide). That's just to get started it will also require many more things. I hope this thread is a joke.