To unlock characters, beat the game on any difficulty. To unlock the final character, beat the game on Admiral difficulty.
Captain Difficulty Setting
Successfully complete the game under the Commander difficulty setting.
Admiral Difficulty Setting
Successfully complete the game under the Commander difficulty setting.
All Seal Weapons
Successfully complete the game under Ensign difficulty setting. You will also get the 12 gauge pump shotgun and the semi automatic shotgun.
All Terrorist Weapons
Successfully complete the game under Lieutenant difficulty setting.
All Sas Weapons
Successfully complete the game under Commander difficulty setting.
All Spetsnaz Weapons
Successfully complete the game under Commander difficulty setting.
Multiple Grenade Launcher
Successfully complete the game under Captain difficulty setting.
Oicw Weapon
Successfully complete the game under Admiral difficulty setting.
Songs
Complete the game under the indicated difficulty setting to unlock the corresponding song in the Jukebox option.
Beach Bossa: Captain
Brazilicious: Captain.
Contortion: Lieutenant.
Dance Of The Unknown: Lieutenant.
Dark In Your Heart: Captain.
Gnostec: Lieutenant.
Infiltrator: Lieutenant.
Insertion Suite: Lieutenant.
KGM: Lieutenant.
SOCOM II Finale: Captain.
Tari Tari: Lieutenant.
Secret Headset Commands
Yell 'Intimidate' into the headset while your crosshairs are on the enemy to make him/her surrender more easily. Your SEAL team will then yell at the enemy to 'Get on your knees!', 'Drop your weapon!', or 'Hands in the air!'.
Make Hq Repeat Themselves
When on a mission, HQ sometimes gives you orders or tells you what the next move is. If you do not hear what she says, say 'I said' in your headset. She will repeat the last thing she told you over the headset.
Seeing Without Night Vision Goggles
Adjust the contrast on your screen or your brightness for dark levels on multi-player and single player levels. This will make night vision goggles unnecessary. This works very well on Frostfire and ShadowFalls and can be done in single player mode and online.
Third Person Night Vision Goggles During Online Play
Whenever you are in a level that allows you to use night vision goggles (for example, Shadowfalls, Rats Nest, Desert Glory), you can eliminate first person night vision goggles. To do this, hold Select and press Up(2), Back, Up. The night vision goggles will now be activated, but the view will be in the normal third person. This makes game play and vision much easier.
Bonus objectives
There are many different ways to achieve bonus objectives. In almost every level, you can complete a bonus objective by listening in on conversations (for example, in the first level, sneak up and hide in the bushes from the first two sentries), or
there are other ways by gathering intel, capturing Bosses, recon sentries, or blowing something up (for example, in the last level, place C4 on the helicopter).
Seeding Chaos: Easy sniper rifle
After meeting with the informant Mallard, go to the largest section of ruin just past the building that you met him in. There should be a guard patrolling it and a few boxes of ammunition lying around. Once at this ruin, turn left so that you are facing towards the road that connects to the bridge. There should be a small section of wall, on which a Sr-25 SD is located. Getting this weapon will allow you to kill the guards and the sniper in the watchtower easier, which should prevent the alarm from being raised.