Just found a 2D hot seat multiplayer game sitting on my desktop. Download it here. It was made with Game Maker, a game engine by Yoyo Games. Still working on Unity 3D, but I wouldn't count on a post with a Unity-made game soon.
P.S. If you have a Mac and an Iphone check this out!
Note: Sorry for the stupid instructions. I messed around with it one day and I forgot to undo it. The new fixed link should be better.