Click the green flag two times. W or up arrow to move, and use the mouse to point where you are going.Zombies can get blown up by bombs if they touch them,as well as that you can shoot the bombs too.There are packs of bullets lying around because you don't have unlimited bullets. If a heart witha white plus on it is also lying around, you can also take it to give yourself more hearts. Hearts are not shown on screen.
Normal zombies attack weakly, but axe zombies, a bit more.