If you have entered the infinite health cheat into your game you may or may not have had trouble. The other cheats work regularly, but infinite health sometimes does not work. Most of the time when you enter a car. DO not worry though, Sometimes it takes a couple times to work. If you see your health going down at anytime in the game, (for playstation press select) go to the factions screen and enter the infinite health code again ( you,d,u,d,l,r,l,r).
Guess what! In this one near the end the North Koreans get called in and theres this huge gate!!!! You can use a bunker buster and guess what! NOTHING HAPPENS AT ALL! So then the lady says you need a nuclear bunker buster!!! Your best bet is to work for the Chinese