If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
The Stickmen have become thief and you are the cop now. Those relentless stickmen have taken control of an enormous shopping mall. Your superior and colleagues are caught up in a big traffic. So what? You've a licensed gun and endless supply of bullets. It is time to take matter in your hands. This is not about getting medals. It is about saving innocent people and the trust they have on the police force. By the way, your strength will be indicated by the green bar. Keep shooting the stickmen to maintain your strength lest you become weak and lose the battle.
Use mouse to shoot, space bar to reload the gun.