Earth Defense Design

Happy Monday designers!
Hope everyone had a lovely Easter weekend.

Today's design criteria: Design a game with a main premise of defending earth, but not from aliens. (Aliens classifies as any species not of this earth.) Defending earth doesn't mean you have to be a human.
As always, use links, or images to explain your design idea, and post it in the comments.

Template
Designer: Name/Alias
Game Title:
Rating:
Genre:
Player count:
Platform(s):
Distribution Method:
Price:

Game Summary:
At least one paragraph describing your game idea and why it would be fun to play. Also describe a few key mechanics that make your game stand out from existing ones.

Have some fun with this one, it's pretty wide open.
Design!