To unlock all single player and multi-player levels in GoldenEye: Rogue Agent enter DOWN, RIGHT, DOWN, RIGHT, UP, DOWN, UP, LEFT at the extras menu.
All multi-player mode skins
Press Down, Left, Up, Left, Right, Down, Left, Up at the extras menu.
Destroy a machine on The Machinery of Evil
Go to the bottom part, then kill everyone. Next, go to the steps were you started and go to the lump in the ground. Take out your Q Spider and go in the hole. Follow the path to the lift and get it to go up. Then, go to the next hole and blow up the thing at the bottom of the wall. You will then be able to get 007 to enter the door.
Harpoon
When you have a Harpoon and are trying to kill someone else with it, shoot the ground around their feet. This is much easier then trying to shoot the person's body. You may even kill more than one. Do not try this with other weapons such as pistols, machine guns, commandos.
Multi-player mode: Shields
When your opponent uses his or her shield, hit them with your stun power. They will be unable to hack out of it because their shield drains all of their power. Then, pick them up and throw them. When your opponent uses MRI Vision, use your shield. You will become invisible to them. Try different combinations of weapons to see which works best for your fighting style.
Opponents with names
Use the following trick when you are trying to kill an opponent with a name above their head. When you spot one of them, go for them before you try to kill anyone else, they always have a good gun. Kill them with a shotgun or strong gun. Pick up their gun, then go around killing their other teammates.
Paintball mode
Press Right, Left, Right, Left, Down, Down, Up(2) at the extras menu.
Unlock multiplayer skins, maps, and artwork
At the end of a level, you see your score and these symbols that come up at the bottom of the screen. They are called Octopi. You can have up to five Octopi. You can unlock different things depending on how many you got on a certain level. In order to get Octopi, you must get enough points from beating the level.
Effect - Code
Auric Enterprises Art - Get 2 Octopi at Auric Enterpirses
Auric Enterprises Art 2, Multiplayer Modifier: Lethal Strike - Get 5 Octopi at Auric Enterprises
Crab Key Art - Get 2 Octopi at Crab Key
Crab Key Art 2, Multiplayer power-up: Speed Loader - Get 5 Octopi at Crab Key
Fort Knox Art 2, Multiplayer Modifier: Random Weapons - Get 5 Optopi at Fort Knox
Fort Knox Art, Goldeneye implant, and SPEC 9 side-arm - Get 2 Octopi at Fort Knox
Hong Kong Art - Get 2 Octopi at Hong Kong
Hong Kong Art, Mulitplayer Power-Up: Adrenaline - Get 5 Octopi at Hong Kong
Hoover Dam Art - Get 2 Octopi at Hoover Dam
Hoover Dam Art 2, Multiplayer Modifier: Eve Overcharge - Get 5 Octopi at Hoover Dam
Midas Casino Art - Get 2 Octopi at Midas Casino
Midas Casino Art 2, Multiplayer Power-Up: Regeneration - Get 5 Octopi at Midas Casino
Multiplayer Map: Bathhouse - Get 3 Octopi at Hong Kong
Multiplayer Map: Carver's Press - Get 3 Octopi at Auric Enterprises
Multiplayer Map: Dr. No's Reactor - Get 3 Octopi at Crab Key
Multiplayer Map: Fissure Platform - Get 3 Octopi at The Octopus
Multiplayer Map: Goldeneye's Retreat - Get 3 Octopi at Volcano Lair
Multiplayer Map: Midas Vault - Get 3 Octopi at Midas Casino
Multiplayer map: Pump Room - Get 3 Octopi at Fort Knox
Multiplayer Map: Turbine - Get 3 Octopi at Hoover Dam
Multiplayer Skin: Auric Elite - Get 4 Octopi at Fort Knox
Multiplayer Skin: Dr. No - Get 4 Octopi at Crab Key
Multiplayer Skin: Dr. No Elite - Get 4 Octopi at Auric Enterprises
Multiplayer Skin: Lair Elite - Get 4 Octopi at Volcano Lair
Multiplayer Skin: Lair Gaurd - Get 4 Octopi at The Octopus
Multiplayer Skin: Oddjob - Get 4 Octopi at Midas Casino
Multiplayer Skin: Triad Informant - Get 4 Octopi at Hong Kong
Multiplayer SKin: Xenia Onatopp - Get 4 Octopi at Hoover Dam
Octopus Art - Get 2 Octopi at The Octopus
Octopus Art 2, Multiplayer Modifier: Rapid Eye Recharge - Get 5 Octopi at The Octopus
Volcano Lair Art - Get 2 Octopi at Volcano Lair
Volcano Lair Art 2, Multiplayer Modifier: Turbo - Get 5 Octopi at Volcano Lair