City Siege 4: Alien Siege is an action shooting game where you can deploy different troops, rescue humans, and fight aliens in this 2D side-scrolling shooter. Arm yourself with advanced units and lazer guns and take on the evil plants from this crazy world. After all they have valuable gems we need… Oh, and there are also some humans they abducted for you to save. Get out there and kick some alien-plant butt!advanced units and lazer guns and take on the evil plants from this crazy world. After all they have valuable gems we need… Oh, and there are also some humans they abducted for you to save. Get out there and kick some alien-plant butt!