Waterloo Labs put together a system that allows you play your NES using your eye movements. It isn’t exactly an elegant control system, but it could be very useful for people with disabilities who want to game, but cannot use traditional controllers.
That looks a lot more frustrating than just not being able to play. If you have to keep taking your eyes off the action, how are you supposed to keep track of what’s happening? I thought it would work more like, tracking where you’re looking on the screen, and just interpolating input based on that. For instance, in order to make Mario run, look at the space a few blocks ahead of him. To jump, glance over his head. That would work without silly wires attached to your face.