(FYI, it can take a few seconds to start depending on if the server went into idle mode)
Server Source Code:
One of the player's in the game is a bot that spins randomly and moves up and down, of course other people have to be playing for you to see others.
Edit: I guess I should also add that this was just to see if it was actually possible to implement a form of multiplayer. I doubt this is optimized in the slightest, and I'm also new to Snap! so I'm sure it could be better, thanks!