Invincibility:
Press Start to pause game play, then press Up, Down, Left, Right, Left, Right, 
White, Black at the options screen. 

Unlimited ammunition:
Press Start to pause game play, then press Left, Right, Up, Down, Up, Down, 
Black, White at the options screen. 

All missions:
Press Up, L, Down, R, Left, L, Right, R, Up at the mission selection screen in either 
single player or cooperative campaign mode to unlock all missions in that mode. 

View game developers:
When playing in two player mode, go to the mission where you have to protect 
Furious Thug. At some point you will reach a room with a lot of chairs and a jury 
stand in the front. Look at the walls until you see some pictures. They appear to be 
the game developers. 

Get inside building:
When playing in two player mode, at some point you will reach a mission where 
you start behind a big pile of sand. First, clear everyone on the other side of the 
sand pile. Then, go back to the sand pile. Get directly on top of it and you will see 
a ledge beside the pile. Walk on the ledge and keep going until you reach a new 
area. You are now inside, or close to the entrance of the door.

Mission 10:
Mission 10 ( the last level) is just an outgoing mission. All you have to do is 
eliminate everyone or restrain a few people. Do not worry about stealth. Just take 
aim and run and shoot. You will not fight Carter and do not worry about trying to 
get better parts on your gun for the mission.

Compliance:
In every level you are required to arrest a certain number of suspects. Instead of 
shouting, if you prefer the assault rifle just shoot the suspects four times then 
shout for compliance. Sometimes they will give up[ others may die. Test this 
strategy on different people and find which ones may die when you shoot them.

On any solo or co-operative mission, choose the shotgun and shoot terrorists in 
the lower stomach region. They will put their hands up immediately, or as soon as 
you shout at them. If your aim is slightly off, change to tranquilizer (Y) and nail 
them with four to six shots or one magazine. They will fall to the ground, ready to 
be cuffed.