Beat the game once and the Extreme difficulty level will be unlocked.
11/14/2001
Strengthen Yourself
Do 100 pull-ups while hanging from a ledge (press the R2 and L2 buttons to do a pull-up) and your grip strength meter will increase.
11/14/2001
Camera Control in Cut-Scenes
During a cut-scene, you can press R1 to zoom in, and use the right analog stick to move the camera around.
11/15/2001
Codec Craziness
While watching any Codec conversation, move the left & right analog sticks and the character's faces will move. Press on one of the sticks, and the faces will zoom in close. Press the R1 or R2 button while Snake or Raiden is listening to someone, and you can hear their thoughts! Some of the guys' secret attitudes toward the other characters are quite funny!
11/16/2001
Alternate title screen.
Beat the game once and the title screen will change.
11/18/2001
Pants-less Marines
Enter Hold 1 or 2 on the ship (right after the first boss fight...the Hold rooms are where the Marines are listening to the Commander give his speech). Once inside of either one of the first 2 Hold rooms, creep past the Marines, and look back at them from the north end of the room, so you can see their faces. In each Hold room (or at least one of them), you should spot a few Marines without any pants on (don't worry, they still have some white boxer shorts, though).
Not really a trick, but a cool Easter Egg nonetheless. =)
11/18/2001
Happy Birthday!
At the first node you log into in the Plant Episode, you're given a chance to input your name, birthday, bloodtype and nationality. If your birthday matches with the same date thats set in your PS2 (most likely you set it to the correct day) you'll be greeted by a Happy Birthday logo with a matching Birthday cake.
11/21/2001
Radar Girl on the Big Shell
As you wait for snake in the Arsenal Gear corridor, a video will start playing on your radar- DO NOT answer your codec to see the whole video.
11/24/2001
Snake's Dogtag
After Snake Gives you the High Frequency Blade and Equipment, knock him out and shake him to get his dogtag.
11/24/2001
Hideo Kojima Dog Tag Information
When first playing as Raiden, enter the name ''Hideo Kojima'' into the first node. It will automatically put in Hideo Kojima's blood type, birthday, sex, and nationality.
11/26/2001
Transportation With Boxes
Take a cardboard box to Strut E: Parcel Room. Get in the box, and jump onto the conveyor belt, in the top right-hand corner of the room. You will be transported to a different area, based on the box you used. Try them all, and see where you go!
11/26/2001
Revenge of the Seagulls
If you shot enough seagulls with any gun, they'll come and either crap on you or come right up and peck you! Similer to the chickens in Zelda.
11/26/2001
Digital Camera
Beat the game and load the same game. you should have the camera in your inventory
Beat the game. Select "Tanker". Get more than 60 dog tags.
Bandana (gives you infinite ammo)
Beat the game. Select Tanker. Get over 30 dog tags.
Blue Wig (gives you infinite 02)
Collect all the dog tags.
Shaver
Grip yourself over behind the caged fence when you start with Raiden.
12/17/2001
Konami Code Solid
At the clear code screen, quickly press Up, up, down, down, left, right, left, right, X, O. You will then hear Snake yell to confirm the code. It does nothing, it's just funny.
4/18/2002
Useless Secret: L2 Start Menu
On the title menu hit L2 and the screen flashes now.
9/29/2003
Control Projector
In Tanker Hold #2, press the button by the projector in the back to change the screen that the image is on. Do it enough and a picture of a woman will appear.
10/7/2004
Metal Gear Posters
In the shell 1 core, go to B2. In the main computer area, there are posters of previous Metal Gear games and other games by Hideo Kojima.
10/11/2004
Hostages in Shell 1 Core B1 Hold
During the Ames search mission, the hostages change depending on the time Raiden meets Ninja after the Fatman battle and the internal clock of the PS2 console. 0:00AM ~ 0:59AM -> all Jennifer 1:00PM ~ 1:59PM -> all old man 10:00PM ~ 10:59PM -> all old lady
11/1/2004
Easily cross minefields.
If you don't have the mine dector, but would like to cross a minefield with receiving damage, just go over to the area where you believe mines are and crawl over the area. Not only will you be unharmed, but you'll also obtain any claymore mines that you crawl over!
12/2/2004
Toy of Raven
You remember Raven from MGS. well in tanker when you first enter you see a shadow of Raven but you find its just a toy. shoot the toy and it will fire balls at you.
12/3/2004
The Shaver
If you get the shaver at the beginning of the plant chapter (by jumping over the rail and going into the enclosed area with the space suit within) you will give it to pliskin when you first meet him. Doing this will have Snake clean shaven at the end of the game. This is vice versa as well if you want a "rugged" Snake do not pick up the shaver!
12/15/2004
Computer Room Cameo
While in the Computer Room, look at the walls in First Person mode. You'll see the photo of Charlie's Angels that happened to appear on the cover of FHM magazine.
1/4/2005
Halt timer in tanker mission
During the tanker mission, while the timer is running, you can temporarily stop it by knocking out one of the two guards running the cameras on the platforms in Hold No. 3.
1/27/2005
Yoji Shinkawa Dog Tag Info
When first playing as Raiden in the plant chapter, enter the name Yoji Shinkawa into the first node. It will automatically put in all of his statistics.
2/1/2005
dog tag information
use the BINOCULARS to identify the names of the person on the dog tag.the name will appear above the enemy.
2/1/2005
Unlocking grip levels
When you are hanging from a ledge, a Grip Gauge appears on screen. By doing a ton of pull-ups (press L2 and R2 simultanously), you can increase the Grip Gauge and increase the alotted time that you are able to hang from a rail.
Do 100 Pull-ups after unlocking Grip Gauge Level 2
2/10/2005
Taking Vamp's best attack away from him
When Vamp's health gets low, he begins to periodically unleash a shadow attack that will prevent you from being able to move; however, if you shoot out the four lights in the room, Vamp will be unable to use the attack.
2/23/2005
Dazing a guard
When a guard spots you, either an '!' or '?' will appear above his head, depending on the distance between you and him. If you shoot this before it dissappears (It's really tricky), the the guard will become dazed for a while and some white bubbles float around his head, giving you a chance to run.
4/8/2005
Faster pull-ups
You can do pull-ups a lot faster by doing a drop catch. A drop catch is when you are hanging from a ledge, and then drop down, catching the ledge below. A drop catch is a total of 10 pull-ups!
4/14/2005
Control the title screen background.
All you have to do is move the right analog stick and the background will move in the direction that the analog stick was moved. It also will change the color of the background. It is useless but it is fun.
4/19/2005
Unlockable Ending Rankings
Every difficulty setting has unique unlockable rankings that may be unlocked depending on your performance throughout the game. Below are the possible unlockable rankings and the requirements to unlock them.
Under 3hr clear, under 3 alerts, 0 kills, 0 escapes, 0 continues, 0-3 rations, no special items
Doberman - Hard Difficulty (Tanker-Plant)
Under 3hr clear, under 3 alerts, 0 kills, 0 escapes, 0 continues, 0-3 rations, no special items
Hound - Normal Difficulty (Tanker-Plant)
Under 3hr clear, under 3 alerts, 0 kills, 0 escapes, 0 continues, 0-3 rations, no special items
3/20/2006
Boss Survival & Others (PAL Only)
After completing the Full Game(Tanker & Plant) you can unlock some special features, but only in the PAL version of Metal Gear Solid 2: Sons of Liberty.