Impostor Zombies

In the game "Imposter Zombies" you must protect the inhabitants of your city and destroy all the impostors. An army of monsters will march towards the gates. On the walls of the city will be installed special bows and arrows. You will be able to lead them. You need to calculate the trajectory and power of the shot and shoot it. For this, you will gain points. After accumulating a certain number, you can buy new types of weapons.