Press Up(2), Down(2), Left, Right, Left, Right, B, A during game play. The message "God Activated" will appear to confirm correct code entry. Note: This only seems to effect you, and not your team or hostages.
Press Up, Down, Up, Down, click Right Analog-stick(2) during game play. Rainbow weapons will shoot red laser trails and opposing force weapons will shoot blue laser trails.
Click Left Analog-stick(2), click Right Analog-stick(2), press X, Y, B, A, B, A at the main menu.
Switch to terrorist hunt map
Once online, go to mission then return to team survival. Choose Hotel or Nuclear Facility. Instead of being the original map for it, it will be the Terrorist Hunt map. The terrorists are still in the game -- be careful. Also, it might have "0" next to the stars for your connection and it will not rise. This also makes it slightly more extreme to see if you and your opponents can work together, then afterwards kill each other.
Basement Level Of Ship
This glitch is to get to the restricted basment level of the ship during online play. First you need to start on the green teams side of the ship. The chairs on the right or left side of the ship can be used. You need to get onto the chairs, this is aquired by crouching and standing furiously, until you glitch on them. Then you need someone to stand facing the chairs so you can walk on their gun to the top of the chairs. This may take a few tries. Once on top have the person stand in front of either the chairs facing the basement or the edge of ship, this does not make a big deal but will affect difficulty. Once you have decided which way you will go you will need him to croush down, stand in position and walk on him to either get to the basement side or front side it will be different difficulties and placements for each side. For basement side you will need to slide of him to the opening so you fall down, hopefully you don't touch the railing and fall off his head to a safe landing, but if not then you will lose around 3 bars, maybe even all. So be careful! But, if you chose the other way, the front of ship you will need to get on the front then have him in between you and the basement area. Run over him to the basement and you will be down, though not the quickest way, it IS the safest. This can be attained easier by using more than just one other person to help you, it could vary from one to a team to make the entire walk.
Ferry Boat Roof
This is just a fun little glitch on the ferry boat online level. When you start from i think red's side, you will need to go up the stairs and to the top of the boat, there will be around the corner a small set of stairs with 3 doors, two down below across from each other and one on your level. You will be on top of the stairs and crouch down. Use your primary weapon to zoom in on the dark blue strip on the roof across from you(near 3rd light)then just hold forward on joystick and walk forward crouched as fast as you can. It may take a few tries but it is for fun and won't affect gameplay much.
When on X-Box Live on the map Agora there is a balcany with 2 garbage bags.(one is big one is small.)walk(or run)into either of them and crouch you should look like the garbage bag.(be careful your gun may stick out and many people may know this glitch.) THIS ONLY WORKS ON ADVERSARAIL MODES!