OH NO!!!!!!!!!!! The zombie apocalypse has started! it's your job to keep the zombies away... for now. You can move left with either left or a you can move right by pressing right or d. To shoot you press the mouse and the power ball come from your hand. To change the colour of the ball press space. If you touch a zombie then you WILL DIE. If you touch one and you don't die once you kill it you will die. Oh also, the score and high score will only show when the first zombie spawns.
I got this idea out of the blue! I didn't play a game or see from a website so it was basically all me. (if there's a game similar, the sorry, because I probably won't know it.)