Extra Blood and Gore

When you start the 1st level, after the video (of you jumping out of a chopper in to terrorist land) push Left, Left, X, Right ,Circle, R1, R2,
L2, R2. This will give you all the guns and a couple extra little bonus', The 2x barreled shotgun.  If you cycle your inventory you will also find the double sided commando blade. Try coming up behind an enemy and put him in a choke.

Pick level

Beat the game with using Lieutenant JG difficulty

Lieutenant JG Difficulty

Beat the game with using Ensign difficulty

Lieutenant Difficulty

Beat the game with using Lieutenant JG difficulty

Lieutenant Commander Difficulty

Beat the game with using Lieutenant difficulty

Commander Difficulty

Beat the game with using Lieutenant Commander difficulty

Captain Difficulty

Beat the game with using Commander difficulty

Rear Admiral Difficulty

Beat the game with using Captain difficulty

Admiral Difficulty

Beat the game with using Rear Admiral difficulty

Get multiple Grenade launcher

Finish the game 3 times

Terrorists Weapons

Beat the game ranked "ensign" and unlock terrorist weapons in armory.

Multiple Grenade Launcher

"Bravo open/close door"(when close to a door--point at it with the crosshairs) "Hand up,get down" (sneak up to guards and yell it)    "Breech,Bang,Clear"(clear a room by pointing crosshairs into it-your team will throw in two bang, grenades, and a frag)    "Bravo diffuse bomb" (when pointing crosshairs at bomb)     "Team low profile"(team sneaks around killing terrorists stealthy) "I got a gun!What do you got?"

Easy Kills

In level 4 go prone and go under the huts and blow wholes in the floor. The enemy wont no what hit'em.
P.S. Throw a flash bang or a smoker in the window first.
P.S.S. When more enemies come after the final hut throw frags way out behind the hut while your still on it, then kill anyone who charges, then crouch and move silently around the perimeter of the back of the island and kill the surviving snipers.