Big Head mode...
	Change weapon loadouts in Mult...
	Invisibility mode...
	Multi-player weapons and gadge...
	Slightly Faster Reload...
	Tag mode...
	Wilhelm Scream...

Enter <477MYFR13NDS4R3SP13S> as a case-sensitive code. Big Head mode will now be on in Local Multi-Player games. Reset the game to its default options to return to normal.

Hold 2 and press Left or Right on the Nunchuk or D-pad.
Hold Minus and press the Left Analog-stick or D-pad Left or Right on a Classic Controller or Pro Controller.
Hold Z and press A on a GameCube controller. The scoreboard will appear. Then, press Left or Right.

Enter Inv1s1bleEv3ryth1ng as a case-sensitive code. The "Invisibility Mode" will be unlocked in the "Multiplayer Split-Screen" section of the "Modifiers" menu. Press B during game play to become invisible instead of sprinting.

Reach the indicated level in multi-player mode to unlock the corresponding item.

Level 2: Reflex Sight (Attachment)
Level 3: AK-47 Assault Rifle (Primary Weapon)
Level 4: Snap Shot (Gadget 3)
Level 5: Sigmus 9 Submachine Gun (Primary Weapon)
Level 6: Distraction (Gadget 1)
Level 7: SEGS 500 Shotgun (Primary Weapon)
Level 8: Heavy Hitter (Gadget 2)
Level 9: Pavlov ASR Sniper Rifle (Primary Weapon)
Level 10: P99 Pistol (Secondary Weapon)
Level 11: Kallos-TT9 Assault Rifle (Primary Weapon)
Level 13: Hi Cap Magazine (Gadget 1)
Level 15: Speed Loader (Gadget 2)
Level 16: Stauger UA-1 Submachine Gun (Primary Weapon)
Level 17: Bio Booster (Gadget 3)
Level 18: PT-9 Interdictus Shotgun (Primary Weapon)
Level 19: Timed Mine (Gadget 1)
Level 20: Silencer (Attachment)
Level 21: Hawksman M5A Pistol (Secondary Weapon)
Level 22: Reactive Armor (Gadget 2)
Level 23: Laser Pointer (Attachment)
Level 25: Terralite III Assault Rifle (Primary Weapon)
Level 26: Toros AV-400 Sniper Rifle (Primary Weapon)
Level 28: Mine Sweeper (Gadget 3)
Level 29: Vargen FH-7 Submachine Gun (Primary Weapon)
Level 31: Kunara V Pistol (Secondary Weapon)
Level 32: Drumhead Type-12 Shotgun (Primary Weapon)
Level 33: ACOG Scope (Attachment)
Level 35: Remote Trigger Mine (Gadget 1)
Level 36: Light Foot (Gadget 2)
Level 37: Talon HL 450 Sniper Rifle (Primary Weapon)
Level 38: Thermal Scope (Attachment)
Level 41: Anova DP3 Assault Rifle (Primary Weapon)
Level 42: Multi Task (Gadget 3)
Level 45: Strata SV-400 Submachine Gun (Primary Weapon)
Level 47: WA2000 Sniper Rifle (Primary Weapon)
Level 50: Last Act of Defiance (Gadget 3)
Level 51: Wolfe .44 Pistol (Secondary Weapon)
Level 52: Masterton M-557 Shotgun (Primary Weapon)
Level 52: Polarized Contact Lense (Gadget 2)
Level 53: Proximity Mine (Gadget 1)
Level 54: Grenade Launcher (Attachment)
Level 55: Gambit CP-208 Sniper Rifle (Primary Weapon)
Level 56: Ivana Spec-R Assault Rifle (Primary Weapon)

This technique takes some practice. As you wait for your gun to go through most of its reload animation, move forward and sprint just before it ends and you'll end your reload faster. This has no effect during the main campain mode, but works in multiplayer. This might not work with all guns.

Enter NotIt!!!11 as a case-sensitive code. The "Tag" option will be unlocked in the "Multiplayer Split-Screen" section of the "Modifiers" menu. Tag mode requires three or more players.

In the Facility Level, after blowing up the fuel tanks, you can hear one of the soldiers do the Wilhelm Scream. GYAAAAA!!!