Metal Gear Solid: Portable Ops cheats and cheat codes for Sony PSP

Passwords:
Null: Input HUNTER-N as a code.
Eva: Input E.APPLE as a code.
Python: Input LQ.N2 as a code.
Gako: Input ! TRAUMER as a code.
Raikov: Input IVN =RV as a code.
Gene: Input ERBE as a code.
Sokolov: Input SATURNV as a code.
Teliko: Input T.F-ACID as a code.
Siginnt: Input DARPA-1 as a code.
Major Zero: Input 1+2-3 as a code.
Cunningham: Input JUNKER as a code.
Venus: Input MGA2VE as a code.
Ocelot: Input R.R.R. as a code.
Paramedic: Input PM-EMS as a code.

Elisa: Input THE-L as a code. 
Note: You cannot unlock her and Ursula at the same time.

Ursula: Input PK +ESP as a code. 
Note: You cannot unlock her and Elisa at the same time.

Unlock Stealth camouflage:
Finish the game with a Technician status level of 99.

Unlock extreme difficulty:
Finish the game. 


Teliko:
Have a Metal Gear Ac!d saved game file on your Memory Stick. 
Complete the entire game two times, then reload your game and Teliko 
will join you.

Venus:
Have a Metal Gear Ac!d 2 saved game file on your Memory Stick. 
Complete the entire game two times, then reload your game and Venus 
will join you.

Major Zero:
Have a MGS: Digital Graphic Novel saved game file on your Memory Stick. 
Complete the entire game two times, then reload your game and Major Zero 
will join you.

Recruiting soldiers:
Go to the Soviet Patrol Base to capture soldiers easily.

Easy reload:
Have two weapons equipped. When you get close to running out in your clip, 
change weapons then immediately change back.