W A S D- to move SPACE- to shoot Health in bottom left corner. Next to it is how much time before you can shoot again. Top Left displays your score and the wave. Raise your score by killing enemies that spawn every wave. Powerups spawn on the ground use them by walking over them. Killing enemies can drop a ticket to the upgrade store where you can get an upgrade. A boss button will appear at bottom right corner after wave 2.
