At the Title screen, highlight "One Player" and hold Square + Circle + L1 + R2 + Select + Up + X.
During play, pause and highlight "Map." Now hold Right + L2 + R2 + Circle + Square + X. After that, just enter the options screen and select "Cheats."
Pause the game, highlight the Map option, then hold Right + L2 + R2 + Circle + Square + X . If you entered the code correctly, you will hear a sound. Then, enter the options screen and choose the "Cheats" selection. This allows the current mission to be successfully completed.
During play, pause and highlight the "Briefing." Now hold Right + L1 + R2 + Circle + X.
More Characters in Multi-Player:
Get to the top of the stairs in the parking garage and you will see a crate that has a M-79 inside. This will unlock the more Syphon Filter 2 characters to be played in 2 Player mode.
Goofies Characters for Multi-Player:
To unlock the "Goofies" characters, you must beat the 2nd level in less than 3 minutes. One way to tell if your gonna get it or not is when you tase Carter (the guard that controlls the electronic door), push the switch 2 times. Then run out through the 2 doors that you just opened electronically. If you can see a guard walking away from you then you're pretty much guarenteed to get it. When you get through the second electronic door just finish the level like you normally would.
Some of the characters you get are: Corpse, Viral Subject, Monk, CBDC Agent, and four others.
Unlock Multi-Player Maps:
There are also hidden items that must be picked up in the single player mode to open some of the locked 2 player arenas. There are 20 Arenas in all. Some of these hidden items, such as the Binoculars, are inventory items and others such as the Girly Mag and Dirty Laundry cannot be seen in your inventory when picked up.
Rockies Multi-Player Map:
Item to find: H11 Sniper Rifle
To unlock the Rockies multi-player map; locate the H11 sniper rifle on the Colorado Rockies level (1st level). The H11 is near the waterfall, where you first meet Chance. Don't jump over the waterfall chasm! Instead, from the edge of the chasm; drop down into the tunnel. The H11 is in there.
Rhomer's Bunker Multi-Player Map:
Item to find: PK-102
In the streets of Moscow; there will be two cars that try to run you down. Before you see the cars, pull out your tear gas launcher. When the cars drive at you; jump up and grab the pole, then fall down, turn around and shoot the three agents with your teargas launcher. After this, go loot their items and search the tail end of the cars to find the PK-102.
Pharcom Site Multi-Player Map:
Item to find: Girlie Mag
The girlie mag is in the Pharcom Lab. Use the taser on the guards. Go through the Mars exhibit and there you are. *Note: The Girlie Mag will NOT show up in your item inventory.
Agency Computer Lab Multi Player Map:
Item to find: M79
Get the M79 in the Operating Room in the Agency Bio Lab Escape level. The Operating Room is the room where Elsa was talking about Liver cells with the two scientists. To get there, go into the vent that you came in from, and follow the hallways. The M79 is at the top of the Operating Room.
Caves Multi-Player Map:
Item to find: Binoculars
Find the binoculars on the Colorado Iinterstate 70 level. They are located behind the first closed door on your left. Press triangle to reveal a passage. Go left, open another door, and enter the room. The box containing the binoculars is in this room.
D.C. City Park Multi-Player Map:
Item to find: Dirty Laundry
Locate the dirty laundry; in one of the washing machines in the first Sniper Building of the New York City Slums District level.
Surreal Multi-Player Map:
Item to find: Biz-2
You must reach the white car in the Volkov Park level before the agent blows it up and locate the biz-2 gun.
Ajier Prison Multi-Player Map:
Beat Ajier Prison Break In level, without using the crossbow.
Club 32 Disco Basement Multi-Player Map:
Kill the first 4 body gaurds before they throw a grenade. This is on club 32
Jungle Multi Player Map:
Kill Archer with one shot as he rides on the chopper. VERY HARD!
Syphon Filter 1 Characters in Multi-Player:
- Beat the C-130 Wreak Site in under three minutes to unlock a playable character from the first Syphon Filter.
-In the New York sewer level, go to the top of the stairway in the parking garage, past the M79 men and open the crate with the M79 in it.
Hidden Movie Theater:
During game play, pause the game and highlight the Briefing option. Then, hold Right + L1 + R2 + Circle + X. You should hear a sound to confirm correct entry. Enter the options screen and select Cheats to view movies.
Hidden Movie Theater (The old fashioned way):
Beat the game on the Easy difficulty setting to unlock all but four of the hidden movies. Unlock the remaining four movies by beating the game on the Hard difficulty setting.
Hidden Sniper Rifle:
When you are parchuting in at the begining of the game, you can land on the rock behind the guy with the broken leg and get a H11 sniper rifle.
Get Ammo From Allies:
All you have to do is zap your friends with the hand tazer. This will knock them out and then you can take their ammo.
Get The UAS_12 Weapon:
Pause the game and go into weaponry, highlight shotgun and press and hold down L1 + R1 + Square + X + Select + Left (simultaneously) the weapon should appear in the weaponry.
Fire the .45 through the tear gas launcher:
In the Moscow Streets level, after you zap the two Russian Militia guys who are shooting at the agent and you grab the tear gas launcher from the back of the police car; equip the tear gas launcher. Walk up to a wall, and then (standing right next to it) fire the tear gas directly at the wall. Wait a second or two, then pause the game, go to the weaponry screen, and equip the .45, and exit. Upon resuming, you should notice that Lian is coughing and you are still holding the tear gas launcher, despite the picture in the lower-right hand corner indicating that the .45 is equipped. If you properly executed this procedure, you are now able to fire the .45 through the tear gas launcher. (*Note: If you change weapons or die, or even if you safely reach a checkpoint, you must perform the code again. Also, this may work on other weapons, I'm not sure.)
Immortal Gabe in Multiplayer Mode:
Just when Gabe is dead and lying on the ground, shoot his head with a rapid-fire weapon (such as HK-5, M-16,G-18...) before he vanishes.When he comes back there should be no health or armor. ( Oh no !!!! Gabe is Immortal). *Note: Second player must be gabe.
In any area where you can hang on a ledge this will work. In 2 player mode get one person to hang low enough so that the other person can knife him. There, you're a zombie! If you want to exit the stage you have to be in a level where you can fall to death. So that the game goes back to normal mode. Oh yeah the zombie can't do anything but run and climb and he's immortal.
Enable All Levels
Infinite Ammo At Weapon (Pick-up)
Stop timer Lvl 2
Stop timer lvl 3
Note: If you use any of the ammo codes with the Game Shark Pro, then you must disable the codes at the main menu and enable them again once a game begins.
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