- Multiplayer weapons and gadgets
Reach the indicated level in Multiplayer mode to unlock the corresponding item:

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

- Switch weapon loadouts in Multiplayer mode
During a split-screen match in Multiplayer mode, keep pushed 2 and press Left or Right to change your weapon. On a Classic Controller or Pro, keep pushed Minus and press Left Analog-stick Left or Right. On a GameCube controller, keep pushed Z and press A. When the scoreboard appears, press Left or Right.

- Invisibility mode
Enter 'Inv1s1bleEv3ryth1ng' as a case-sensitive code to unlock the 'Invisibility Mode' option at the 'Multiplayer Split-Screen' section of the 'Modifiers' menu. While you are playing this game, press B to become invisible instead of sprinting.

- Big Head mode
Enter '<477MYFR13NDS4R3SP13S>' as a case-sensitive code to activate Big Head mode in 'Local Multiplayer' games. Reset the game to its default options to return to normal.

- Tag mode
Enter 'NotIt!!!11' as a case-sensitive code to unlock the 'Tag' option at the 'Multiplayer Split-Screen' section of the 'Modifiers' menu. Tag mode requires three or more players.