The human race has finally achieved space travel, and with it, they have built a utopia in space. But on this space station there has been a droid revolt. Now they are trying to blast their way through the gates! Save humanity and defeat the waves before they can get in. Use gold to build turrets to defeat the waves of droids in each gate. Upgrade your turrets, and build more barricades in order to help stop the stronger droids at the higher level gates. Build up your base, and upgrade it until you can go through all the gates and save mankind's utopia!