Splinter Cell: Double Agent - Elite mode

Hint: Bonus skin:
Reach the indicated rank to unlock the corresponding skin:

Spy second skin: "Recruit" rank.
Spy third skin: "Special Agent" rank.
Uspilon Forces second skin: "Field Agent" rank.
Uspilon Forces third skin: "Commander" rank.

Alternate endings:
Complete the indicated task during the final mission to see the corresponding ending after the bomb is disarmed.

Ending A Good: Have NSA trust above 33 and save at least two of the three targets cruise ship, Hisham, and Lambert.

Ending B Normal: Have NSA trust below 33, and save the cruise ship, Hisham, and Lambert. Alternately, allow two of the targets be destroyed but have NSA trust above 33.

Ending C Bad: Destroy all three targets. Alternately, destroy two targets and have NSA trust below 33.

Bonus equipment:
Complete the following special objectives in single player mode to unlock the corresponding item.

Electric Lock Pick: Primary objectives in JBA HQ 1.

EMP Device - Enhanced: Primary objectives in JBA HQ 1.

EMP Grenade: Secondary objectives in the Iceland Assignment.

EMP Grenade - Attachment: Secondary objectives in the Cozumel Assignment.

Explosive Sticky Camera-Attachment: Secondary objectives in the Iceland Assignment.

Frag Grenade - Attachment: Primary objectives in JBA HQ 3.

Gas Grenade: Primary objectives in JBA HQ 1.

Gas Grenade - Attachment: Secondary objectives in the Cozumel Assignment.

Hacking Device - Force Hack Upgrade: Primary objectives in JBA HQ 2.

Hacking Device - Software Upgrade: Secondary objectives in the Shanghai Assignment.

Night Vision - Enhanced: Primary objectives in JBA HQ 3.

Shotgun Shell - Attachment: Secondary objectives in the Okhotsk Assignment.

Smoke Grenade - Attachment: Secondary objectives in the Shanghai Assignment.

Sonic Grenade - Attachment: Primary objectives in JBA HQ 2.

Ultrasonic emitter: Secondary objectives in the Ellsworth Assignment.

Wall Mine - Flash: Secondary objectives in the Okhotsk Assignment.

Wall Mine-stun: Secondary objectives in the Ellsworth Assignment.

Kinshasa: Extended level
At the end of the ninth mission, Kinshasa, when you have a sniper to shoot Hamza Hishima do not shoot him. If you do you will complete the mission. If you do not, the crane you are on will fall down. Then Emile will yell at Sam for missing Hishima. Sam angrily turns off his radio and the level in now extended for several minutes.

Kinshasa: Secret tool
At the beginning of the mission you must go up a elevator. You will then get a checkpoint. When you enter this room, take out the guards. Make sure you are not wearing your sunglasses. When you walk in the next, big, room, the sun should be shining in your eyes. Flip your glasses down and you can see guards shooting out the windows you were looking at. Go to the right as soon as you walk in. Try not to draw too much attention. If you keep going to the right you will hit a window. An icon should appear at the bottom of the screen, indicating that you can use something. Press X and Sam will get out a small black tool, clip it on the window, whiz it around, then pull off a small circle that he has cut from the window. If you push forward on the window, Sam will put his legs through and squeeze through the hole so that he is now outside