Achieve the indicated rank to unlock the corresponding items in Multiplayer mode:
1st Lieutenant (214,000 experience points): Headgears 4 (Half-Face Mask, Reinforced Helm, Tactical Goggles)
2nd Lieutenant (172,000 experience points): Camo 3 (Pink, Blue, Woodland, Wasp, Sand, Crimson)
Captain (264,000 experience points): Merc Weapons (MG36, SPAS12, Deagle)
Colonel (535,000 experience points): Headgears 5 (Ballistic Face Mask, Riot Helm, NVGs)
Corporal (14,500 experience points): Camo 1 (Desert, Urban, Russian, Guerrilla, Fall, Desert 2)
Elite (675,000 experience points): Camo 5 (Custom 1, Custom 2, Custom 3)
First Sergeant (109,500 experience points): Headgears 3 (Bonnie Hat, Beret, Tinted Goggles)
Lt. Colonel (425,000 experience points): Camo 4 (Yellow Urban, Red Urban, Tiger, Rust, Urban 2, Grey)
Major (330,000 experience points): Military Armor (Vier Recon Armor, Diamondback Combat Armor, Anaconda Assault Armor)
Master Sergeant (82,500 experience points): Freedom Fighter weapons (AK47, Raging Bull, SV98)
Private 1st Class (3,000 experience points): Headgears 1 (Tactical Helm, Balaclava)
Sergeant (23,500 experience points): Tactical Armor (Raven Recon Armor, Vulture Combat Armor, Falcon Assault Armor)
Sergeant First Class (56,500 experience points): Camo 2 (Flecktarn, Orange, Swedish, War2k5, Alpen, White)
Sergeant Major (139,000 experience points): Black Market Armor (Typhoon Recon Armor, Cyclone Combat Armor, Hurricane Assault Armor)
Specialist (8,400 experience points): Rainbow Weapons (MP7A1, SIG552, USP40)
Staff Sergeant (38,500 experience points): Headgears 2 (3 Hole Balaclava, Baseball Cap, Breathing Mask)
Use your thermal goggles after you deploy a smoke grenade to see better.
Play the Fremont Street level and look for a ledge that has a bottle of Axe cologne. Shoot the bottle and the neon roof of the Fremont Street Experience will change to an animation of a girl in a bikini with some Axe items. This is followed by a sequence with outtakes and early animations.
When Jung must hack the computer to open the door to Irena, enemies rappel down from the windows. Before you tell him to hack, send your team to the far side of the room over near the fenced area. Then, run behind the computer and tell Jung to hack it. A trigger will activate and the enemies will start pouring into the room. Your team will take most of them out on the way to the computer. If someone on the team goes down, Jung will stop moving towards the computer and sit there (or Michael, depending on who goes down). Once there is a pause in the battle, tell him to heal your partner. You can then order them around as usual. During this time, Jung was supposed to be hacking the terminal, but killing all the enemies skips this part. Once done, tell Jung to hack it again. He will open the door to Irena. Michael will get left behind. Watch yourself; there are enemies on the stairs above you and will pick you off as you come up, especially on on the Realistic difficulty setting.
When the mission begins, make your squad rappel down the left part of the building. Then, order them to go down until they are able to breach. Next, go to the middle of the roof with the opening. Drop a C4, incendiary, smoke, or frag grenade, and keep shooting through the glass. After a few seconds, order your squad to breach into the building. Finally, rappel down into the building.
In the Dante's Casino level near the arcade, there is a machine labeled Tom Clancy's: Splinter Cell: Chaos Theory.