Metal Gear Solid 4 Cheats

Passwords

Once you beat the game you unlock an option called "password" at the extras menu. Enter the corresponding codes to unlock the following:

Desert Eagle Long Barrel: Enter "deskyhstyl" as a password.
Mk. 23 (SOCOM from Metal Gear Solid): Enter "mekakorkkk" as a password.
Mosin Nagant: Enter "mnsoymsyhnto" as a password.
"Gekko" iPod song: Enter "GEORGE" as a password.
"Mobs Alive" iPod song: Enter "ABRAHAM" as a password.
"Desperate Chase" iPod song: Enter "THOMAS" as a password.
"Midnight Shadow" iPod song: Enter "THEODORE" as a password.

Otacon Codes

In Act 4: Shadow Moses, Nuclear Warhead Storage B2, when at Otacon's office, he will ask you for the code. Enter one of the following codes instead of the one that Otacon mentions to get the corresponding bonus:

100,000 DP: Enter "14893" as a code.
"Opening - Old L.A. 2040" iPod song: Enter "78925" as a code. (This song increases Snake's accuracy.)
"Policenauts Ending" iPod song: Enter "13462" as a code. (This song causes soldiers held by Snake to fall asleep when touched.)

Infinite Drebin Points

First, acquire the drum can. You do this by finding the soldier that is hiding in the can, and using it as a bathroom. After that, go up ahead a few feet, where you will see three crates. When you have gone past them, you will see just two crates. You will also see about three rebel soldiers fighting. One is carrying an RPG and the other two have machine guns. They will die and respawn continuously. You will have a chance to pick up the RPG after the soldier has died three times. Do so because each RPG is worth 6,000 Drebin Points. The important thing is to stay anywhere behind the two crates, otherwise the trick will not work. Going further than the two crates will stop the respawning loop of the soldiers dying. The only way to get the RPG without breaking the respawning loop is to use the Mk II.