The story at the beginning sets the plot perfectly for the game play. You should stick to the given briefings to fight against the monsters and aliens who will look to swarm you down in this war game. There are so many different types of weapons and abilities to avail but remember you will need money for that purpose. You can hide behind solid places or stay out of the range of the enemies to get some breather before recomposing and re-launching attacks. The best way to break the unity of the enemies is by moving very efficiently. This tactic increases your chances of being more effective during the wars. You will have to prove that you truly are the best soldier the planet earth has ever known.