SuperCheats.com have now published their guide to Metal Gear Solid 4 and Metal Gear Online.

There is a complete walkthrough, details of all the unlockables and some hints and tips.

The guide is accompanied by screenshots from the game and in-game videos.

It's free to look at, and there is a printer friendly option on all the pages.

The guide can be found here:
http://www.supercheats.com/guides/metal-gear-solid-4/

The Passwords menu is unlocked after you have complete the game once. Just go look at the extras menu.

1aytmmymhk: Unlocks 1911 Custom (a powerful silenced pistol)

Abraham: Unlocks "Mobs Alive" iPod tune

Aottrykmyn: Unlocks Altair Costume

Deskyhstyl: Unlocks Desert Eagle (Long Barrel)

George: Unlocks "Gekko" iPod tune

Jmsotsynrn: Unlocks Type 17 Pistol

Mekakorkkk: Unlocks Mk.23 Pistol

Mgo2play: Unlocks the "Subsistence Action" iPod tune

Mnsoymsyhn: Unlocks Mosin-Nagant sniper rifle

Pkhhnwhsjt: Unlocks Patriot (SMG with huge power, unlimited ammo and no reloads)

Skynytktjp: Unlocks the Mk. 2 scanning plug

Theodore: Unlocks "Midnight Shadow" iPod tune

Thomas: Unlocks "Desperate Chase" iPod tune

Tshsniammr: Unlocks Thor .45-70 (one-shot-kill pistol)

Complete the game once and go back to Debrin. There you can purchase various extra ammo items, different grenades and bandanas.

Complete the following tasks to get the corresponding Emblems. There are 40 in total and each ones brings a different reward, that might be a special item or weapon.

Ant Emblem
Shake down 50 enemies for items

Assassin's Emblem
Complete the game with less than 25 alerts and more than 50 of both knife kills and CQC holds. This will give you the ALtair Costume from Assassin's Creed.

Bear Emblem
Choke 100 enemies to death

Bee Emblem
Utilise the Scanning Plug S or Syringe on 50 enemies

Big Boss Emblem
Complete the game in less than 5 hours on the highest difficulty with no deaths, no alerts, no kills, no recovery items (rations, regains or noodles) , no stealth suit and no bandanna items. This will give you the Big Boss face camo.

Blue Bird Emblem
Give away 50 items to friendly soldiers

Centipede Emblem
Get less than 75 alert phases, less than 250 kills, and over 25 continues.

Chicken Emblem
Get over 150 alert phases, more than 500 kills, more than 50 continues, use more than 50 recovery items (rations, regains or noodles) and complete the game in over 35 hours.

Cow Emblem
Activate over 100 alerts

Crocodile Emblem
Do more than 400 kills

Eagle Emblem
Make 150 headshots

Fox Emblem
Complete the game in less than 6 hours on at least normal mode with no deaths, kills, recovery items (rations, regains or noodles) , stealth suit or bandana items and with less than 5 alerts

Fox Hound Emblem
Complete the game in less than 5.5 hours on at least normal mode with no deaths, kills, recovery items (rations, regains or noodles) , stealth suit or bandana items and with less than 4 alerts

Frog Emblem
Make over 200 dives or rolls

Gecko Emblem
Be pressed against walls for a total of at least 1 hour

Giant Panda Emblem
Complete the game in more than 30 hours

Gibbon Emblem
Hold up 50 enemies

Hawk Emblem
Be admired by 25 friendly soldiers

Hog Emblem
Make 10 combat highs

Hound Emblem
Complete the game in less than 6.5 hours on at least normal mode with no deaths, kills, recovery items (rations, regains or noodles) , stealth suit or bandana items and with less than 4 alerts

Hyena Emblem
Pick up 400 dropped weapons

Inch Worm Emblem
Have a total crawl time of more than one hour

Jaguar Emblem
Get more than 75 alert phases, less than 250 kills, and less than 25 continues

Leopard Emblem
Get more than 75 alert phases, less than 250 kills, and over 25 continues

Little Gray Emblem
Collect all 69 weapons

Lobster Emblem
Crouch for at least 2.5 hours in total

Mantis Emblem
Complete the game in less than 5 hours on at least normal mode with no alerts activated, continues, or recovery items (rations, regains or noodles)

Octopus Emblem
Complete the game without activating any alert phases

Panther Emblem
Get over 75 alert phases, more than 250 kills, and less than 25 continues.

Pig Emblem
Use at least 50 recovery items

Pigeon Emblem
Complete the game with no kills. This will give you the bandana. Alternatively you can also receive the bandanna from Drebin for 5,000,000 DP after you complete a new game + (that would be a new game after you have completed the game at least once)

Puma Emblem
Have less than 75 alert phases, make less than 250 kills, and less than 25 continues

Rabbit Emblem
Look at 100 Playboy pages

Raven Emblem
Complete the game in under 5 hours

Scarab Emblem
Roll forward over 100 times

Scorpion Emblem
Have less than 75 alert Phases, less than 250 kills, and have less than 25 continues in total.

Spider Emblem
Have less than 75 alert phases, over 250 kills, and over 25 continues.

Tarantula Emblem
Get less than 75 alert phases, make over 250 kills, continue more than 25 times.

Tortoise Emblem
Hide in either an oil drum or card board box for at least 60 minutes in total.

Wolf Emblem
Complete the game with no continues, or recovery items (rations, regains or noodles)

When you have beaten the game once on any difficulty setting go to the 'Extras' screen and then 'Password' and enter the following passwords to unlock the corresponding iPod song.

Unlock 'Gekko' iPod Song:
Enter the password george

Unlocks 'Midnight Shadow' iPod Song:
Enter the password theodore

Unlock 'Desperate Chase' iPod Song:
Enter the password thomas

Unlocks 'Mobs Alive' iPod Song:
Enter the password abraham

If you enter the following codes instead of the code Otacon tells you to at Shadow Moses you'll receive the indicated bonus after the 'Access Denied' scene.

Unlock 100,000 DP:
Enter the code 14893

Unlock iPod song:
Enter the code 13462

Unlock iPod song:
Enter the code 78925

If you're viewing a cut-scene and you notice Snakes psyche gauge suddenly start to decrease just press X rapidly to replenish it.

Below is a list of over 70 weapons which are featured in the game and can be obtained one way or another.

Pistols

1911 Custom
Desert Eagle
Desert Eagle (Long Barrel)
Operator (Colt .45 with Extended Barrel)
Solar Gun (Affects Enemies Psyche and Recharges in Sunlight)
Race Gun (Fires Ricochet Bullets)
Type 17 (Broom Handle Machine Pistol)
Thor .45-70 (Rifle/Pistol)
Mk 2 Pistol (Tanq)
Mk.23 SOCOM
Five Seven
Glock 18C
GSR (.45)
PSS
PMM

Assault Rifles

XM8
An94
G3A3
Mk.17
Ak102
M4 Custom
FAL Carbine


Sniper Weapons

DSR-1


Sub-Machine Guns

M-10
Mp7
P90
Bizon
MP5sd2
Patriot (Unlimited Ammunition)
VZ. 83 Skorpion


Heavy machine guns

M14EBR
M60E4
M82A2
HK21E
RAIL GUN
MK.46 Mod 1
PKM
SVD
VSS
Mosin-Nagant
Tanegashima (Very Slow loading old flint lock, 33% of hits cause a whirlwind which makes enemies drop items)


Shotguns

M870 Custom
Twin Barrel
Saiga-12


Grenade Launchers

MGL-140
XM25


Rocket launchers

Fim-92A (Stinger)
M72A3
RPG-7
Javelin


Weapon Modifiers

Flashlights
Suppressors
Dot sights
Scopes
Fore grips
Grenade launchers
Laser sights
Masterkey (under Barrel Shotgun for Assault Rifles)


Others Weapons

Knife
C4
Claymore
Grenade
Stun Grenade
Molotov Cocktail
Sleeping Gas Mine
Chaff Grenade
White Phosphorus Grenade
Sleep Gas Satchel Charge
Smoke grenades (Yellow, Red, Green and Blue)

To unlock the Solar Gun you must collect 5 statues, these can be found at the following locations.

Frog Statue
Middle East - Stage 1:
On top of the Nomad vehicle in Advent Palace garage.

Octopus Statue
South America - Stage 2:
Research Lab boss room, upper right room.

Raven Statue
Europe - Stage 3:
Top floor of the human phase of the Boss fight.

Wolf Statue
Shadow Moses - Stage 4:
Behind Snake's starting spot in the human phase of the Boss fight.

Mantis Statue
Outer Heaven - Stage 5:
Near the northern-most door during the human phase of the fight.

If you have no more use for any camoulage you may be wearing and want to discard it shake the Sixaxis controller and Snake's Octocamo will return to it's neutral black and blue pigmentation.

Complete the game and create a saved game file, then reload the saved game and encounter Metal Gear II in the first stage to retain Drebin points, weapons, ammunition, special items you collected in the original game.

The following bonus face paints can be unlocked for game use by completing the indicated task.

Unlock Metal Gear Solid Snake Face Paint:
Start the Shadow Moses level.

Unlock Young Snake Face Paint:
Start the Eastern Europe level.

Unlock Young Snake with Bandana:
Start the Eastern Europe level.

Unlock Big Boss's Face Paint:
On a Single-Player session get the Big Boss emblem.

Unlock Drebin Face Paint:
Buy and keep more than 60 different weapons.

Unlock Raiden Mask A Face Paint:
Using the Metal Gear II during the intermission scene shock Sunny.

Unlock Otacon Face Paint:
Using the Metal Gear II during the intermission scene shock Dr. Emmerich.

Unlock Raiden Mask B Face Paint:
Using the Metal Gear II during the intermission scene shock Dr. Naomi Hunter.

Unlock Roy Campbell Face Paint:
Using the Metal Gear II during the intermission scene shock Colonel Campbell.

Unlock Screaming Mantis Face Paint:
Using non-lethal means defeat the Battle Beauty (human form) Screaming Mantis.

Unlock Laughing Octopus Face Paint:
Using non-lethal means defeat the Battle Beauty (human form) Laughing Octopus.

Unlock Crying Wolf Face Paint:
Using non-lethal means defeat the Battle Beauty (human form) Crying Wolf.

Unlock Raging Raven Face Paint:
Using non-lethal means defeat the Battle Beauty (human form) Raging Raven.

Unlock FaceCamo Face Paint:
Defeat the Battle Beauty Laughing Octopus in overall battle. This face paint functions like the Octocamo suit but only on your head.

To get this camouflage which will make you totally invisible you must complete the game in Single-Player mode without triggering the alert phase. It can also be purchased from Drebin for 5,000,000 DP when you start another game session after completing the game.

The following disguises which will help you remain undetected during the different stages of the game are unlocked when you go to the indicated area or complete the corresponding task.

Unlock Civilian Clothes:
Start Eastern Europe level

Unlock Altair (Assassin's Creed) Rags:
Get the Assassin emblem

Unlock Middle East Militia Disguise:
Go to the safe house in the Middle East.

Unlock South American Rebel Disguise:
Go to Cove Valley Village in South America.

Unlock Business Suit:
Clear the game once.

When you complete Single-Player mode once the following features will become available options.

Unlock New Combat Vests:
Complete Single-Player mode once.

Unlock Big Boss Extreme Difficulty:
Complete Single-Player mode once and then save the cleared game data.

These useful items which will help you in missions are unlocked by completing the indicated task during gameplay.

Unlock Bandanna:
On any difficulty complete a Single-Player session without killing anyone. This item will give you infinite ammunition.

Unlock Stealth Item:
Without setting off a single alert (doesn't include Cautions) complete a Single-Player session on any difficulty setting.

Unlock Scanning Plug S:
On the same profile as your Single-Player game have more than 10 hours of Metal Gear Online play time. When you have his you can purchase the item from Drebin.

Digital Camera:
Found in the Nomad vehicle during the mission intermission. A special photo is unlocked when you collect this item in stage 4.

Get these weapons by completing the indicated task during gameplay.

Unlock World War I Colt 45:
On a Single-Player session earn the Hound emblem.

Unlock Desert Eagle (Long Barrel):
On a Single-Player session earn the Fox emblem.

Unlock Thor 45-70 (Rifle/Pistol):
Earn the Fox Hound emblem on a single-player session

Unlock Patriot Future Assault Weapon:
On a Single-Player session earn the Big Boss emblem.

Unlock Race Gun:
Clear the Single-Player game once. This weapon fires ricochet bullets.

Unlock Solar Gun:
Using non-lethal means on their respective idols collect the 5 statues (4 Battle Beauties and the Frog Soldier/Haven Troopers in stage 1). This weapon affects enemies psyche and recharges in sunlight.