The best way to kill evil alien soldiers is to not be seen.
It's a safe bet that since the dawn of time - and the dawn of warfare - human beings have been thinking to themselves, "You know, I bet I could get rid of that jerk Unga much more easily if he couldn't see me coming." Invisibility is one of the all-time classic superpowers: Harry had his cloak, Frodo had his ring, and Wonder Woman had her invisi - er, bad example.
Now, the main character of Crysis 2 joins the field with his super high-tech Nanosuit, as displayed in the trailer you see here to the right. While some of the uses of the Nanosuit's invisibility power seem a bit obvious (stealth up behind an enemy, even though his back is to you and you have a gun) some seem rather creative - lay explosives at your foes' feet, then retreat a safe distance and blow them to kingdom come.
Really, it's the creepy rendition of Sinatra's classic "New York, New York" that sells this. As cool as Crysis 2 looks here, we have to remember that Monty Python was teaching us all how not to be seen decades ago.