Over-the-top and highly cinematic, it's the FPS version of "The Rock".
As far as the single player campaign is concerned, it plays out just like the first except more intense and bombastic. The game alternates between the Americans and Brits who are fighting the enemy in Afghanistan and Russia. You can also play as Russian Terrorists in an optional mission that resembles the bank robbery scene in "Heat" than an army game. Everything in MW 2 is quickly paced and set to the thundering musical score of Hollywood composer Hans Zimmer (making his video game debut). Unlike Treyarch's "World at War", don't expect long, drawn out battles, though. Like "Modern Warfare", the missions are quite short enough to encourage replayability. Story-wise, the game has been amped up considerably and is quite over-the-top in its scenarios. Imagine "Black Hawk Down" directed by Michael Bay and you'll get the idea.
So far, I haven't played online, but I've seen the new options which include the ability to customize killstreak bonuses. The number of weapons in MW 2 is staggering and I had fun playing with all of the new toys Infinity Ward has placed in the game. You can also dual-wield machine pistols and hand guns "Halo"-style. Visually, the game is staggering. It looks even better than the first game due to combination of many special effects and more detail. Personally, my favorite mission, so far, is the first stealth mission in the snow. It's very cinematic and right out of a James Bond movie in which you use ice picks to climb to a top of a snowy mountain. Overall, "Modern Warfare 2" is a action gaming experience; the best one this side of the "Metal Gear Solid" franchise.