Your main task is to defend points from zombies, don't let them get to you. You are the last hope of the village. You will be paid coins, so I think you will not be lost.
On the computer: Shoot - Left mouse button Pause - P or TAB On your phone, drag your finger on the screen to move the scope and press the button to shoot. Pass levels on 3 stars, get coins for it and spend them to buy and improve weapons.