Look around using the mouse, and press space to shoot energy bullets (you can hold down space for rapid-fire). Move your mouse anywhere on the screen and click to move; your character moves to the spot that your mouse pointer was when you clicked.
v1.3.6: title card changed v1.3.5: invisible zombie reworked v1.3.0: dodging zombies replaced with growing zombies v1.2.5: minor bugs fixed v1.2.0: invisible zombies slightly nerfed v1.1.0: dodging zombies are released v1.0.0: game + zombie, ghoul, and invisible zombies make their debut.