Pirates space ships attack you and your mission is to kill all of them by placing towers which you can upgrade and make more efficient in shoot. There are fake 3D effect which makes it even more interesting and cool.

For each ship that you destroy you receive a small amount of cash. That cash can be used again to level up your towers. Some ships even drop special items. That way you can get in possession of meteoroids, more money or vortexes. You click on the towers and once you've got enough cash on hand, you can upgrade it three times. Mostly, the first upgrade is a about higher shooting range, the second one gives you more damage, the third one increases the shoot rate.