I'm using Ubuntu 14.10. I have a laptop that is connected to a monitor. The laptop lid is closed and I use the monitor with an external mouse and keyboard. The laptop screen is off. Whenever I try to play the game in fullscreen, it switches to only use the laptop screen, and turns the monitor off.
Similar to this problem. As I said above, the laptop screen is off, but it is still detected in system display settings.
Additionally, there is no sound. My volume is up all the way on my computer and on Rising World.