You have to build defenses to protect the land against an alien invasion that seeks to destroy humanity.
How to Play:
You'll have to choose the best place to place towers and can get money when you kill your enemies in order to buy upgrades for your towers and make them more powerful.
Game play:
It has a very useful and simple tutorial when your first start playing. There is also a variety of towers and upgrades with the option of merging power to create more powerful towers.
Controls:
It is operated with the touch screen, you need to tap on the menus to select towers and weapons and then simply slide your finger to place or change their position or to merge them together.