Games Tower defense Clone Annihilation from space

My current project is a Tower-Defence Clone. The title of the project is "Annihilation from Space".

The rough story:

A Great Mother Spaceship (naturally hostile) visits Earth and wants to destroy one city after another. Your job is to prevent this. With skillful placement of the defensive towers, you should succeed.

So it will be about fending off feidary spacecraft waves. Different towers are then available for this purpose.

There will also be many uprates. However, the balance between the opponents and the defensive towers is quite difficult.

It's a german project.

http://www.pchobbyspieleschmiede.de/index.html