The rocket launcher in Killzone 2 is pretty awesome. IGN had only had the Sixaxis controller in their hands for a few minutes when they ran across the behemoth and hoisted it onto their shoulder, but as they ducked down a dark alleyway and lightning crackled overhead, they couldn't wait to use the thing.
Killzone 2 doesn't happen on Vekta, the setting of the first console outing and Killzone: Liberation. Instead, you take the fight to the enemy's home world of Helghast. This puts your team at an immediate disadvantage. After living on the godforsaken rock for years, the Helghastians have grown accustom to living in survival suits and harnessing the constant lightning for their massive anti-aircraft cannon.