Enter The Matrix

To jump off a wall, put your guns away, enter Focus and jump toward the wall. When you are about to hit the wall, press Jump and you will flip off the wall in the air. If you want to do a bullet jump (the jump that you do in a battle with guns), draw your guns before you get to the wall and press Jump at it. Then, shoot away. You cannot shoot while flipping though.

When doing a wall flip in Matrix mode, press Jump to do a longer flip. Note: You will not be able to fire your weapons while doing this. Be careful, and try not to use it around a lot of enemies.

Go to the gate where the two men are pinned down by SWATs. Enter first person mode and pick-off all the SWATs. The two men will say, "We owe you a lot Ghost/Niobe", and the other/your gate will open. You can now complete the mission successfully.

Successfully complete the game as Ghost, then enable the "Unlimited health" and "Unlimited ammunition" codes. Play the chase levels where many Agent Smiths are chasing you. Get to the point where you get the grenade launcher. Use the grenade launcher to take out the Agent Smiths. This requires about two to three hits from the grenade launcher. Continue until the last part just before the final sequence in the Matrix before you get on the platform and kill the Agent duplicates. Look directly ahead at the top of the balcony. You can see Niobe walking into the mini pillars. If you kill her, you will die even with the "Unlimited health" code. Fire the grenade launcher at her, and she should climb up the fencing and walk off the building completely.

First when you get into the level, take out your M240. Then, turn to your left until you see the helicopter. Start shooting and follow the helicopter until you see it go down. This is a fast way to complete this part, and is easy to do.

There is a way to skip the entire level. Jump down off the truck and run to the right in Focus mode. You will see a fire escape ladder that you would usually see later in that level. Climb up the ladder and go up the stairs. You will reach a door. Go through it. Go through two more doors to complete the level.

Get a gun (preferably a machine gun) and switch to first person view. Shoot and you will see that the bullets appear in a perfectly straight line, no matter what the weapon. This is extremely useful and works with any gun.

Approach a Powerade vending machine and press Action near the buttons on the machine. A Powerade will pop out.

In the Nuclear Plant level where you get the UMP, look at the wall just before you go up to the tower to find a Powerade vending machine.
The Pupster.

If you have low health and are in trouble, go to a Powerade machine. Press Action and a Powerade will pop out of the machine. Run on top of it, and if done correctly it will fill up your health.
joshua.

At the beginning, turn and run to the top of the stairs on the right. Next, hide your weapon, run in matrix mode, and jump across the gap. If done correctly, you should grab onto the railing on the other side and just go up some flights of stairs to end the level quickly.

When an Agent pushes you, you can recover from it. When he pushes you down, hold L + Z to recover from the fall. Make sure you are not in Focus before he pushes you.