I have an existing running game source code. I need to modify and add online multiplayer function to it.
Just like Appstore "Fun Run" https://itunes.apple.com/us/app/fun-run-multiplayer-race/id547201991?mt=8
1. Allow online players up to 4 players at a time. At least 2 players to start game
2. Invited facebook friends
3. Able to select friends to play with
Show me your portfolio on those multiplayers app you have done.
Please do not bid unless you have experiences with developing online multiplayer features.