WORLD NEWS, GLOBAL RANK and LOCAL RANK you can found this menu in the RANK menu.
What is WORLD NEWS:
World news is a total number of aliens destroyed this week for all contributor in the world.
What is GLOBAL RANK:
Globar rank is a your high score from kill the enemy for all country.
What is LOCAL RANK:
Local rank is a your high score from kill the enemy from your local country.