checked-no =>Arcade Mode: Complete Campaign mode on any difficulty to unlock Arcade Mode. =>Mile High Club: To unlock this level, complete the Campaign once. =>Unlockable Options: After completing Campaign mode once, you'll be able to earn unlockable cheat and bonus options by collecting pieces of Intel. These options will appear under the Options/Pause menu as you collect pieces of Intel. * 2 Intel - CoD Noir * 4 Intel - Photo-Negative * 6 Intel - Super Contrast * 8 Intel - Paintball * 10 Intel - Cluster Bombs * 15 Intel - A Bad Year * 20 Intel - Slow-Mo * 30 Intel - Infinite Ammo =>Golden Guns: Complete the listed requirements to unlock the Golden versions of each gun. * AK-47: Complete all Assault Rifle Challenges. * Desert Eagle: Become at least a level 55 Commander. * Dragunov: Complete all Sniper Challenges. * M1014: Complete all Shotgun Challenges. * M60E4: Complete all LMG Challenges. * Mini-Uzi: Complete all SMG Challenges. =>Multiplayer Unlockables: As you progress through the experience levels in multiplayer, you'll unlock upgrades and extras for the multiplayer mode. Here is a list of what you'll earn when you reach each listed experience level. 2 - Demolitions Class 30 - Killer Challenges 1 3 - Sniper Class 31 - M1014 4 - Create-a-Class 32 - Bandolier (Perk 1) 5 - Gun Challenges 33 - Killer Challenges 2 7 - M21 34 - R700 8 - Last Stand (Perk 3) 36 - Killer Challenges 3 9 - Boot Camp Challenges 1 37 - G36C 10 - M4 Carbine 38 - Overkill (Perk 2) 11 - UAV Jammer (Perk 2) 39 - Killer Challenges 4 13 - Mini-Uzi 40 - P90 14 - Bomb Squad (Perk 1) 41 - 3x Frag (Perk 1) 15 - Boot Camp Challenges 2 42 - Humiliation Challenges 1 16 - M1911 43 - Desert Eagle 17 - Martyrdom 44 - Dead Silence (Perk 3) 18 - Boot Camp Challenges 3 45 - Humiliation Challenges 2 19 - M60E4 46 - M14 20 - Sleight of Hand (Perk 2) 47 - Humiliation Challenges 3 21 - Operations Challenges 1 48 - Humiliation Challenges 4 22 - Dragunov 49 - Barret .50 Cal 23 - Claymores 50 - Humiliation Challenges 5 24 - Operations Challenges 2 51 - Elite Challenges 25 - G3 52 - MP44 26 - Iron Lungs (Perk 3) 53 - Elite Challenges 2 27 - Operations Challenges 3 54 - Elite Challenges 3 28 - AK-74U 55 - Golden Desert Eagle 29 - Double Tap (Perk 2) 55 - Prestige Mode