You can unlock the following rewards by meeting the Killstreak requirements below:

• 3 - UAV (Reveals enemies on minimap)
• 4 - Care Package (ammo / killstreak air drop -- can be collected by anyone)
• 4 - Counter UAV (disable enemy maps)
• 5 - Sentry Gun (airdropped)
• 5 - Predator (directed missile)
• 6 - Precision Airstrike (choose a location to bomb)
• 7 - Harrier Strike (choose a location to bomb and defend with a Harrier)
• 7 - Attack Helicopter (helicopter backup)
• 8 - Emergency Airdrop (four ammo / killstreak air drops -- can be collected by anyone)
• 9 - Pave Low (armored helicopter backup)
• 11 - Chopper Gunner (operate a helicopter gun)
• 11 - AC130 (operate a plane gun)
• 15 - EMP (disable enemy electronics)
• 25 - Nuclear Strike (kills all members of both teams)

The following weapons and equipment can be unlocked by attaining the (multiplayer) levels below:

Assault Rifles

• FAMAS - Lvl. 1
• M4A1 Carbine - Lvl. 4
• SCAR-H - Lvl. 8
• TAR-21 - Lvl. 20
• FAL - Lvl. 28
• M16A4 - Lvl. 40
• ACR - Lvl. 48
• F2000 - Lvl. 60
• AK-47 - Lvl. 70
• M14 EBR - Campaign Only
• G3 - Campaign Only

Submachine Guns

• UMP .45 - Lvl. 1
• MP5k - Lvl. 4
• Vector - Lvl. 12
• P90 - Lvl. 24
• Mini Uzi - Lvl. 44

Light Machine Guns

• L86 LSW - Lvl. 1
• RPD - Lvl. 4
• MG4 - Lvl. 16
• AUG HBAR - Lvl. 32
• M240 - Lvl. 52

Sniper Rifles

• CheyTac Intervention - Lvl. 1
• Barrett .50 Cal (AKA M107) - Lvl. 4
• WA2000 - Lvl. 36
• M21 EBR - Lvl. 56
• Dragunov - Campaign Only

Secondary Weapons

• PP-2000 - Machine Pistols Lvl. 1
• Glock 18 - Lvl. 22
• M93 Raffica - Lvl. 38
• TMP - Lvl. 58

Shotguns

• SPAS-12 - Lvl. 1
• AA-12 - Lvl. 12
• Striker - Lvl. 34
• Ranger - Lvl. 42
• M1014 - Lvl. 54
• Winchester 1887 - Lvl. 67
• W1200 - Campaign Only

Handguns

• USP .45 - Handguns Lvl. 1
• .44 Magnum aka Colt Anaconda - Lvl. 26
• M9 - Lvl. 46
• Desert Eagle - Lvl. 62
• M1911 - Campaign Only

Launchers

• AT4-HS - Lvl. 1
• Thumper x2 aka M79 grenade launcher - Lvl. 14
• Stinger - Lvl. 30
• Javelin - Lvl. 50
• RPG-7 x2 - Lvl. 65

Other

• Frag Grenade - Lvl. 1
• Semtex - Lvl. 1
• Throwing Knife - Lvl. 7
• Tactical Insertion - Lvl. 11
• Blast Shield - Lvl. 19
• Claymores - Lvl. 31
• C4 - Lvl. 43
• Knife
• Ice Picks
• Smoke grenade
• Stun grenade

  Attachments

• Red Dot Sight
• EOTech Holographic Weapon Sight
• MARS Sight
• ACOG Sight (and various telescopic sights that are specific to certain guns)
• Thermal Scope
• Suppressor
• Grenade Launcher
• Heartbeat Sensor
• Shotgun
• Extended Magazine
• Full Metal Jacket ammunition (replacement for Deep Impact)
• Sniper Scope (will not take up an attachment slot, just like in Call of Duty 4)
• Akimbo
• Rapid Fire (replacement for Double Tap)
• Foregrip
• Tactical Knife