Click green flag twice. Arrow keys or wsad to move. click or hold to shoot. Avoid and shoot the zombies Each zombie has 3 health, you have 5 health. If your health bar is blue, it means you have extra health. The blue things give you 1 of the 4 power ups, speed, health, fire speed and big bullets for extra damage. An orange boss with 20 health will spawn every 15 points you get. Once defeated, you'll get 5 points.