TO: You people saying 'copy down your name if you want multiplayer'. Your idiots. If it was a simple thing to add multiplayer, nearly everybody would have it in their games. For real-time multiplayer games you need a socket server (program) to connect to, and to run that socket server, you need to your own server (computer) to run it on. It's easy enough for you to sit their and say we want multiplayer, but its the developer who would have to pay the monthly fee for the server; quite likely more than what they'd be making through advertising per month.
Your instructions are harldy instructions at all. Might want to actually tell people to click on the right hand side, and to actually click (some games you're supposed to circle).