It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

This game would greatly benefit from controller support, especially with multiplayer. I played this over the weekend with my partner, we used Steam Big Picture overlay and emulated mouse with our controller. Not a great experience but it was better then trying to pass a mouse and keyboard back and forth while sitting in the living room.