If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
The bad day at a laboratory, no one is alive there. Now, there are only zombies who want eat brains. It’s worldwide crisis, we have no cure against zombies gene. Fortunately, there are strong soldiers in the army who decided go to the laboratory and try to kill all 35 zombies. You are one of these two men.