Periodically, Konami releases a few new codes that games can use at the password input area in Metal Gear Solid 4. This area is only available to those who have already completed the game once, and typically unlock hidden content that most people wouldn't normally have access to.
Previous codes include:
Enjoy!
Source
• skynytktjp - Mk. II Scanning Plug
• mgo2play - "Subsistence Action" song for the in-game iPod
• mgo2play - "Subsistence Action" song for the in-game iPod
Previous codes include:
• mekakorkkk - .45 caliber pistol
• mnsoymsyhn - Mosin-Nagant rifle
• jmsotsynrn - Type 17 pistol
• aottrykmyn - Altair outfit (from Assassin's Creed)
• mnsoymsyhn - Mosin-Nagant rifle
• jmsotsynrn - Type 17 pistol
• aottrykmyn - Altair outfit (from Assassin's Creed)
Enjoy!
Source