* Customizable Kill Streaks. Possibly the most anticipated new feature is a pretty darn cool one. You now unlock kill streaks as you rank up, and though you can still only take three into a match with you at one time, you can at least have some control over how many kills you need to rack up to use them. Some of the kill streak rewards require three, four, five, six, seven, nine kills… In addition to old favorites like the UAV, there are things like a care package that's parachuted in and grants you a random upgrade; stationary sentry guns you can put down to beef up defenses, especially in objective-based games; and of course the AC130 gunship, which requires 11 kills to use (and which, consequently, I did not see). Best of all, it seems like kill streaks stack, since I was able to use my five-kill Predator missile, then immediately activate the four-kill care package right afterwards.
* Death Streaks. Death streaks? Yes, you will now be rewarded for dying too many times in a row, in an effort to prevent frustration for those just getting into Modern Warfare 2. The only two in the demo I played were Painkiller, which starts you with a triple health boost after you're killed three times without making any kills of your own, and Copycat, which lets you use the loadout and perks of the last guy who killed you for one life.
* Secondary Weapons Replace Pistols. No more piddly sidearms. Well, not quite true; pistols are still in there if you want them, but you can pass up the lo' Desert Eagle in favor of tactical shotguns, automatic machine pistols, and other nice gear to augment your primary rifle. All these secondary weapons can take attachments just like the primaries can, so if you want to throw a suppressor or digital camo on your shotgun, more power to ya.
* Fancy New Equipment Instead of Grenades. Toss out your frag grenades, if you want, and replace them with some nifty gear that serves a variety of other purposes. Perhaps you would prefer Semtex timed sticky explosives? How about some throwing knives? The most abstract but perhaps coolest piece of equipment I saw was the tactical insertion, which looks like a typical flare when you throw it down. In practice, it acts as a mobile, single-use spawn point, so anytime you're moving into a heated area, throw one down and that's where you'll restart if you die.
* Experience Boosts Galore. It seems like you get experience point bonuses for doing damn near anything in the new game. I'm not just talking headshots; any stylish or meaningful kill is going to give you some kind of experience boost. Kill a guy just before he's about to get a kill streak? Bonus. Take out the guy who just killed you? Bonus. Get the last kill in a match? Bonus. IW says the leveling (which now caps at level 70) has been tweaked to take the faster accumulation of points into account, and you'll get something gameplay-related for prestiging this time around. They aren't saying what, though.
* Callsigns. Infinity Ward has been playing a lot of Street Fighter IV. The title and emblem system from that game is reproduced almost exactly here, with dozens upon dozens of descriptive phrases you can unlock and slap on your profile to give other players a sense of exactly how you've been putting it down online. The titles and emblems you can get will correspond to your behaviors, so if you spend a lot of time camping or you rack up a ton of melee kills, everyone will know it. The titles I saw in this demo version
* NO BETA. THERE IS NO OPEN OR PUBLIC BETA PLANNED FOR MODERN WARFARE 2. NEITHER OF US (YOU OR ME) WILL PLAY IT UNTIL IT'S OUT. THAT'S KIND OF A BUMMER. INFINITY WARD PLEASE RECONSIDER.