Shoot your enemies by tapping them. Each one require several taps. They'll shoot you too! Try to kill as much as possible before your health runs out.
Also availiable in the folowing android markets :
Amazon App Store : https://www.amazon.com/gp/product/B071K65Q74
App Store :http://www.mobilesoftwareapps.org/h21-enemies-attack/
Appsgayser Store : http://app.appsgeyser.com/5126695/Enemies attack