Alien invasion has been an evergreen creative theme, 

especially in the gaming world, 

for there is essentially a new release in such topic every single month. 

Though the trending theory among scientists is that 

extra-terrestrial beings might not all be invasive, 

and they might long have resided on earth 

or even have assimilated with mankind. 

Nevertheless, 

none of us could know for sure 

the ultimate goal of our space visitors.