Keypad codes
Mission 1: Lighthouse
No keypad locked doors
Mission 2: Cargo Ship
No keypad locked doors
Mission 3: Bank
Keypad to left security booth on first floor: 3624
Keypad to right security booth on first floor: 3624
Keypad to main security room: 2306
Keypad to treasurer's office: 8645
Keypad to bank's back door: 3901
Keypad before president's office: 3490
Keypad to safe in president's office: Code unknown, must be hacked
Mission 4: Penthouse
Keypad To Dvorak Room: 0280
Mission 5: Displace
Keypad to door between meeting room and lobby on second floor: 8136
Keypad to door between meeting room and lobby on first floor: 8136
Keypad to CEO's meeting room: 2346
Keypad to CEO's office: 2609
Keypad to fire escape: 3485
Keypad to central server room: Code 2109
Keypad to R&D server room: 9205
Mission 6: Hokkaido
No keypad locked doors
Mission 7: Battery
Keypad to shipping area: 1879
Keypad to elevator: Code unknown, must be hacked
Mission 8: Seoul
No keypad locked doors
Mission 9: Bathhouse
Keypad to owner's office: 3650
Mission 10: Kokubo Sosho
Keypad To Server Room: 1945
Catching Shetland
Have your sniper zoomed-in on the guard. When there is a fight, shoot, run, and catch Shetland. Then, end the mission.
Bank: Invisible laser beam
To avoid detection by the invisible laser trip wire in the entrance of the vault, closely examine the entrance with your thermal goggles on. Then, use your OCP to disable the laser emitter and walk out of the vault. By doing this, you can leave without sounding the alarm.
There is an invisible laser at the entrance to the bank vault. Before you go down, take a guard down with you and into the vault. When you leave, just pick him up and walk out and the alarm will not go off.
Bathhouse: Finding the bombs
After going through the gate when chasing Shetland, the first bomb is directly to the left of the gate that you enter. Go left through a little crevice and you should see a red light flashing. Go to it and disarm it. When you do that, one of Shetland's gaurds will walk up the stairs. Kill him. To get to the second bomb, go up the stairs. Turn left then turn right and look straight ahead. You should see another red flashing light down below the walkway. Hop over the ledge of the railing and disarm the second bomb. When you are done disarming the bomb, jump on to the railing and pull yourself up. Two guards will be to your left, walking on the walkway. They will probably hear you; get ready to kill them. It is fairly difficult to kill them without losing a lot of life, or at least dying. After you kill them, go down the walkway to the back wall. About halfway you will see another red flashing light. Jump across the little gap and disarm it. A guard will come through the back door right when you disarm the bomb. Kill him, then go through the door and meet Shetland. You will then have to make a critical choice; note: pull the trigger. It would be a good idea to quicksave the game whenever you disarm and kill the guards.
Bathhouse: Splinter Cell reference
You must go through the warm baths at one point in the level. There are two guards here. Interrogate one of them and he will tell you that Shetland's elite guards have thermal goggles. He will also add that they will not do much good in steam, because steam is not fog, as in an abbatoir. This is a reference to the original Splinter Cell game, in which Abbatoir is a level.
Displace: Prince Of Persia: Warrior Within reference
While infiltrating Displace International, Sam will encounter two guards talking about Prince Of Persia: Warrior Within. It is in the small cafe next to a laser filled hallway, past a keypad locked door. A second way to access the room is through a vent. However because Sam is inside the vent, the conversation becomes difficult to hear.
Hokkaido: Splinter Cell reference
After you scan Milon Nedich's liscence plate and enter the building, you will overhear some guards talking about ninjas. One will be telling the other that he was stationed on an oil rig and that it was attacked by a ninja. This is a reference to the first Splinter Cell in which Sam is the ninja.
I-SDF Base: Splinter Cell reference
You can overhear a couple of guards talking in the main hall. One will say something about how guarding the place is just like guarding the CIA HQ; nobody would break in there. This is a reference to the original Splinter Cell, in which you must break into CIA headquarters.
Lighthouse: Alternate way to retrieve the radio data
During the mission you will have to overhear some data being said on a radio transmission by a guard. If you fail to do this, you can just find the data in a filing cabinet next to the radio.
North Korea: Half-Life reference
In the missile battery stage, at some point Sam asks Grim if he could use a crowbar to open the console in the battery. She says "That's for geeky scientists". This is a reference at the Half-Life games where you play as a scientist with a crowbar.
North Korea: Ronald Reagan reference
This game was developed at about the same time that Ronald Reagen died. In the missile battery stage, a missile is launched at the USS Ronald Reagen. Grim tells you this and Sam says "You want me to win one for the Gipper?"
Panama: Never set off alarms
When you are close to the part with the lasers, go down there and set off one alarm. Kill all the people. When you cross the lasers, you will not set off another alarm. You can now finish the mission without setting the alarms off when crossing the lasers.
Penthouse: Ubisoft references
In the introduction sequence for the mission, when you see a blimp, you can also see a Ubisoft logo on it.
When you ride the rope in the NYC sign near the helopad in the rooftop, you can see "Ubisoft" on the building you are riding to.
Seoul: Original Splinter Cell music
When you begin the level, you are in a child's room. Immediately exit the room and go to the right. When you reach the end of the hall, in which the walls are blown away, turn to the right and enter a half-destroyed room. There should be a radio inside. Turn it on, and it will play the same music from the cafe from where you started near the Chinese Embassy 2 level on the original Splinter Cell.
Ledge grab
In order to do a better ledge grab, press [A], then when the spy puts his legs up on the thing he is hanging from, press [Forward] while tapping [A].
Moving faster in water
In any mission when you are in water, take your gun out. You will move faster.
Alternate dialogue
When you just see Otomo try to commit suicide, Lambert will radio you and say something. If playing under the normal difficulty setting he will say something similar to "Otomo just tried to commit sepuku. Get in there and revive him". However, if you complete the game under the hard difficulty setting, Sam will say something similar to "Looks like someone feels a bit too good about himself". However, all the objectives will remain the same.