There's a reason I could never join the military and defend our homeworld against all threats, and it's this: I'm unsure the planet is actually round. How can invaders attack? We'll just push them off the size of the world! They'll fall into the cosmos for all eternity! Who needs soldiers when we could just use a bulldozer?! Anyway, let's pretend the Earth is round - really stretch our disbelief a little - and take a look at Earth Defense Force 6, the latest in a long-running series about defending that blue ball amongst the stars.