My only concern is that the weapons are too futuristic and unrecognizable to be considered "modern warfare".
CoD4's main appeal was that the weapons were exactly the same ones soldiers around the world operates.
The heart beat sensor and the gun in the demo was pretty impressive. I can tolerate that, but I still wish the majority of the guns are the good old ballistics spitting firearms we wield in the present.
It's pretty cool seeing the Steyr AUG in the game at least, it confirms that at the very minimum one gun from our time is there. I also think I saw some AK-47's outfitted with red dot sights in the demo. Also in Game Informers article, I saw a Brazillian rebel armed with a Dragunov.
I'm praying the M4A1 Carbine makes a return, as well as the legendary AK-47 and the MP5.
I also expect the futuristic HK416 to make an appearance, maybe also the cancelled XM8 and the SCAR rifles our special forces use today.
Anyways, Modern Warfare 2 is going to be a kickass game.