Well designed, well executed (lol?), incentives to keep playing, and one of the most active online communities ever.
Speaking of controls, well done again, just like MW1. Pretty much the entire COD series has been done with perfection.
I've had a moderate interest in FPS games since Doom for PC, but never had a desire to play online until Modern Warfare 2. After months of nagging from my cousin, i finally picked this up. Now i can't put it down.
Online multiplayers can be frustrating, as you run into all the die-hards who don't do anything ELSE with their lives, but gaining levels and unlocking goodies certainly makes up for getting constantly killed, not to mention gratifying killstreak rewards for doing consecutively well (i catch even myself cussing at the screen until i get that pavelow in the air, then it's all grins & maniacal laughter).