If you’ve played the previous Modern Warfare titles than you are most likely familiar with the leveling system that Infinity Ward installed into the games. Better weapons, attachments, and perks are made available as you gain experience allowing you to customize your gameplay and what you bring into battle with you.
With Modern Warfare 3 IW is adding even more customization to the multiplayer aspect. Their newest addition is called “Weapon Proficiencies”. What this means is that you can level up specific guns as you level up your profile. For example, say you like to play with the M4A1. The more you use it the more XP that gun gains. With that comes specific perks for that gun like less kick, the ability to run faster, or the ability to melee faster depending on what that gun’s perks are.
Take a look at the trailer above as Infinity Ward explains it a bit more and look for Modern Warfare 3 on November 8th, 2011 for Xbox 360, PC and Playstation 3.