Call of Duty: Modern Warfare 3 - PC New Pointstreak system that rewards players both for landing kills and completing objectives Weapons proficiency system that allows you to customize your favorite weapons, making them more effiecent in any map or mode Online/offline 2-player co-op Special Ops Survival mode that earns you experience through 16 frantic objective-based missions New play modes, including: Kill Confirmed mode, Team Defender mode and user generated match modes Integration with 'Call of Duty: Elite,' an online multiplayer oriented service launched simultaneously with Call of Duty: Modern Warfare 3