Zombie Invasion Shooter is a top-down shooter game where you play as a human who must defend yourself from waves of zombies. You can move around the screen using the "A" and "D" keys, and you can shoot zombies using the mouse. You have a limited number of lives, so you need to be careful not to get hit.
As you progress through the game, the zombies will become more difficult to defeat. They will move faster, they will shoot back, and they will come in larger numbers. You will need to kill the zombies fast to survive.
The game also features a scoring system. You get one point for killing a zombie, and you lose one life if a zombie touches you. The game ends when you run out of lives.