The game was developed to make use of muscle stimulation hardware developed by Pedro Lopes. The player connects two electrodes to their arms, which cause involuntary motion in your arm. So if you attach it to specific muscles you can cause particular parts of your hand and arm to move. The technology allows the intensity of the current in your arm to be controlled by the computer.
It was designed to replicate force feedback on devices such as smartphones, but when we were playing around with the kit we loved the sensation of trying to resist the involuntary muscle movement. There's something about that that really makes you aware of how your brain and body work.
In the game you're moving around a laser pointing at your own head, controlled by the mouse. Your aim is to zap the tumours without zapping the fleshy good stuff! But if the laser cuts through a nerve you get an electrical impulse to the arm which needs to be resisted if you want to avoid hitting fleshy good stuff!
Because we wanted the game to be about overcoming involuntary muscle motion we made sure the nerves appeared along your path to the tumours, rather than being something that needed to be avoided. It was counter-intuitive, but worked well as a way to focus attention on overcoming unusual sensations, rather than a way to test manual dexterity.