This game is not ready to be put up. It's not really a game. There's a timer, but no score. The zombies don't attack. you can let them stack up and blast away in the last few seconds- or don't. You can never fire a shot and still get a 'you win" after the timer ends.
Well... not quite. The zombies continue to come after the timer and and the "you win" pops up, and after about 10 seconds, they kill you. Also, rather than getting 1x score per kill, the score continues to add with each click after their head pops off, so you can get extra score. I got 2750.