Frenesis is a 40 level game where you have to protect a cross in the middle of the screen stretching to the edges of the screen from waves of aliens. To destroy the aliens as they move towards the cross from all angles, you have a Statron which is a line stretching to the edges of the screen, made up of arrows that can either move vertically or horizontally along the screen. When you move the Statron the arrows point in the direction of travel and if the end of the arrows hit an alien moving in the opposite direction then it is destroyed.